Person of Interest

Season 5

B.S.O.D.

1. The episode's title, "B.S.O.D", is another computer-referenced title. The meaning is "Blue Screen of Death" - a condition in which a blue screen appears on a Windows computer after it has crashed, because of an error where the system detects that it can't operate safely. This relates to the risky safety state that The Machine was in where things ended in the season 4 finale.
2. Cluster made from PS3 consoles to provide infrastructure for The Machine is not something uncommon. These consoles were somewhat widely used by academic, government and private research facilities to build both powerful and cheap (compared to, i.e. Intel Xeon architecture) computing clusters. As of April 1st 2010, with the release of 3.21 firmware, Sony removed the feature that allowed users to install Linux on their consoles, but one may guess that this fact would not pose a challenge to The Machine.
3. Detective Fusco refers to Harold Finch as "Mister Peabody." Mr. Peabody, one half of the duo "Mister Peabody and Sherman," is a animated cartoon super-intelligent dog that wears glasses.
4. In the flashback where Harold talks to Grace, Grace is walking her dog. In real life the dog belongs to Michael Emerson and Carrie Preston, and is named Chumley.
5. The candy bar the workman was buying from the vending machine that covers the entry to the subway was an Oh Henry! bar, a candy bar originally made by the Williamson Candy Company in Jonathan Nolan's home town, Chicago. It is one of many small Chicago references the show hides in its episodes.
6. The numeric sequence that Harold enters into the candy vending machine to gain entrance to the subway hideout is 3141, which are the first four digits of pi (3.1415926....).
7. An end card states: In memory of our friends / Tommy Heilig / Joel Reynolds / Maciek MalishJoel Reynolds died on 29 May 2015. He worked as Assistant Art Director on 44 episodes of Person of Interest (2011), and has 5 credits spanning 1998-2015, including 1,245 episodes of All My Children (1970).Maciek Malish (1962-2015) died on 12 Sep 2015. He worked as Dialogue Editor on 5 episodes of Person of Interest (2011), and has 126 credits spanning 1987-2017. He won two Emmys for outstanding sound editing for The X-Files (1993) in 1996 and 1997. He was nominated for another 10 Emmys over the course of his career, including for his work on the TV series Lost (2004), The X-Files (1993), Millennium (1996), and The Tick (1994).There is no information about Tommy Heilig, nor is there any information about cause of death for the other two.
8. During the decompression of The Machine, Root says it is "overclocking" and some may think she should have said "overheating". However, overheating is a definite danger when overclocking your CPU. Overclocking refers to making them "run faster" than originally intended and will cause your components to run hotter, and the additional heat will cause problems unless you can properly cool your components.

SNAFU

1. SNAFU is the acronym for the military expression "Situation Normal: All Fucked Up." The expression was coined by U.S. Army troops during World War II. Over time, it has come to be an observation that things are bad, and they've always been bad, and the best thing to do is to focus on making it through the day.
2. There is a flashback along the timeline, but since the Machine is, for the moment, unable to differentiate the past from the present, the moment is designated as "Day R", with the letter 'R' displayed in "Blackboard bold" (a.k.a. "double struck") typeface style, because that is the convention used in Mathematics to denote the set of Real numbers. Real numbers can, of course, be thought of as points on an infinitely long number line. And the Machine is unable to pinpoint the flashback moment's place on the timeline.
3. Tulsa, OK is mentioned for the third time in the series when it is stated that Laurie Granger is from Tulsa. It was previously mentioned in Person of Interest: Root Path (2014), when Root accesses a nuclear power plant in Tulsa and in Person of Interest: Death Benefit (2014), when Reese's Secret Service alias was from Tulsa.
4. On Fusco's cell phone message, he calls himself "The Fusconator."

Truth Be Told

1. 590 Madison: former IBM Headquarters.
2. When Finch is on the laptop in Time Square you can see Jim Caviezel's character John Reese on the top left of one of the video screens.
3. The full text of the poem "Cocoon Above! Cocoon Below!" by Emily Dickinson is:"Cocoon above! Cocoon below! / Stealthy Cocoon, why hide you so / What all the world suspect? / An hour, and gay on every tree / Your secret, perched in ecstasy / Defies imprisonment!An hour in Chrysalis to pass, / Then gay above receding grass / A Butterfly to go! / A moment to interrogate, / Then wiser than a "Surrogate," / The Universe to know!"
4. The binary riddle that shows up multiple times in the episode is "Cocoon Above! Cocoon Below!" by Emily Dickinson.

6,741

1. Shaw accuses Greer of having her strapped to a table for nine months, a nod to the pregnancy Sarah Shahi took a break from the show for.
2. There is no scene in this episode without Shaw in it.
3. 6,741 is the number of the simulation Shaw is in during the episode. Like in the other simulations, Shaw doesn't reveal the location of the Machine. Unlike the other simulations, she waits another hour before killing Greer.

ShotSeeker

1. Fusco calls the team "The Nerd Herd"; a phrase used for the computer geeks on the show Chuck (2007), as a play on The Geek Squad from Best Buy stores. The main character in that show is able to to save people in a similar way as this one because he has a supercomputer in his head.
2. Harvesta is a pseudonym for Monsanto.

A More Perfect Union

1. The phrase "a more perfect union" is drawn from the Preamble to the Constitution of the United States of America. The complete preamble reads: We the people of the United States, in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America. The preamble sets forth a statement of the vision of the newly formed United States of America that will be embodied in the Constitution.
2. The bridge that Shaw and Greer sit by is the same bridge in The Girl on the Train (2016).
3. When asked to sing at the wedding, Harold (as "Uncle Ralph") performs "We're not gonna take it." This song was first released by the American band Twisted Sister in 1984.
4. Samaritan's speaker mentions the "Great Filter," which relates to the Fermi paradox. The filter is the "bottleneck" that exists--if not in our past, then in our future--between death and expanding, lasting life. The inference is that humans' outlook for survival is bleak because a species capable of developing advanced civilizations is likely prone to self-destruction.

QSO

1. QSO is an amateur (ham) radio (or "Q") code used when one operator is making initial contact with another operator. The receiving operator typically responds with a greeting and a signal strength report before a longer conversation begins. Q-codes, like the better known ten-codes (10-4) used by citizen's band radio operators, are used to convey information using brief phrases. Once used widely by maritime, law enforcement, rescue, and aviation personnel, their use is now largely confined to military and amateur radio operators.
2. Fermi's paradox is the apparent contradiction between the high probability that non-human intelligence must exist somewhere in the vastness of the universe and the lack of evidence for its existence.
3. QSO is part of the 'Q code' system, which was invented for early radio-telegraph communication. The Q code system was created to make early radio communication more efficient. Back in the day only Morse code was used, which was quite inefficient. The Q codes were 3 character codes that related to commonly asked questions and or replies. The code 'QSO' means: "Can you communicate with ... directly (or through...)?"
4. QSO also stands for "quasi-stellar object" or "quasar" - extra-terrestrial radio sources that were originally thought to be a sign of advanced, intelligent civilizations.
5. The code that Root sends to Shaw means "four-alarm fire", which is part of the quote of Shaw: "But, you and me together would be like a four alarm fire at an oil refinery."
6. Fusco's hospital room number is 314.
7. The colonial house where the Machine sends Root is the Morris Jumel Mansion at 65 Jumel Terrace in Washington Heights. It is the oldest house in the neighborhood which was declared a national historic landmark in 1961, and later turned into a house museum. It was built in 1765 by Roger Morris, a British military officer, and served as a headquarters for both sides in the American Revolution.

Reassortment

1. The book that Carl G. Elias was reading is Twelve O'Clock High written by Beirne Lay, Jr. and Sy Bartlett which is also a movie directed by Henry King.

Sotto Voce

1. Sotto Voce is Italian for "under the voice", that is, to speak in a low voice for emphasis. The technique is designed to suggest revelation of a secret, or a piece of information that might otherwise shock or offend.
2. This is the episode that Det. Fusco comes to know about the machine.
3. This episode marks the return of the mysterious villain, "The Voice" who had previously appeared in Person of Interest: Last Call (2014).

The Day the World Went Away

1. This is the 100th episode of the show.
2. The episode is named after the Nine Inch Nails song "The Day the World Went Away", that appears in the episode's closing scene.
3. Beginning now, The Machine has chosen its own voice to be that of Root. It can now be confirmed that the voiceover in the opening scene of Person of Interest: B.S.O.D. (2016) is of The Machine itself.
4. Elias hides Finch in the same apartment where Reese hid Elias as "Charlie Burton" in Person of Interest: Witness (2011). The apartment acts as a "bookend" for Elias' relationship with the team.
5. This is not the first time Amy Acker's character has died, only to play another character in the same show. When she played Fred in the TV show "Angel," she died, only to be replaced by the demon God Illyria.
6. In this episode two long running characters die.

Synecdoche

1. Joey Durban (James Carpinello) is Root's (Amy Acker) husband in real life and was the POI from Person of Interest: Mission Creep (2011).
2. This is the first time that Harold has chosen a bird of prey (Osprey) as his alias. The other bird names have been songbirds (Wren and Finch) or fish-eating birds (Gull and Whistler). Birds of prey (raptors or Accipitriformes) are apex predators which have keen eyesight, strong talons and a sharp curved beak.
3. Synecdoche is a rhetorical term where a part of something is used to label the whole. Among the most commonly used of these expressions is "The White House", which refers to the Executive Branch of the United States Government (i.e. the office of the President of the United States.) In other uses, an individual proffering assistance might offer to "lend a hand", the hand serving as a metaphor for the whole person.
4. Freon wasn't the first controversial discovery by Thomas Midgley Jr. Previously he discovered that the toxic compound tetraethyl lead, when used as an "anti-knock" gasoline additive, made the automobile internal combustion engine incredibly more efficient. His discovery resulted in world-wide lead contamination in the environment.
5. The computer virus Harold works with ("Ice 9") shares the name as a deadly form of water that freezes at room temperature from the Kurt Vonnegut Jr. novel "Cat's Cradle".
6. Marine Helicopter Squadron One (HMX-1) has several helicopters and MV-22 Osprey tilt-rotor craft and is responsible for the transportation of the President of the United States, Vice President, Cabinet members and other VIPs. Only when a helicopter has the President aboard does it use the call sign "Marine One".
7. After Reese says take a shot at the president now Shaw says whatever you say Wilkes Booth.She is referring to the famous stage actor and later president assassin John Wilkes Booth who shot and killed president Abraham Lincoln.
8. John Reese's SSN is 498-00-3145. The first three digits are known as the area number because they were assigned by geographical region; 498 indicates it was issued out of Missouri. The middle two digits are the group number; 00 is never used so this is an obvious fake. The final four digits is the serial number; John is the 3145th person in the "498-00-" group.
9. The three new assets The Machine chose in Washington, D.C. have similar characteristics to Finch, Shaw, and Reese. Pierce is Finch because he is the tech genius with the money. Harper is Shaw because she is wild and doesn't play by the rules and Joey is Reese because he is the military man that wants to help others.

.exe

1. The 802.11 wireless modem that Resse and Shaw take from the evidence locker is tagged as having been collected from the residence of Edward Snowden in 2013 and also has an i.d. number of 80211.
2. "Ice-9" is a reference to Kurt Vonnegut Jr.'s novel "Cat's Cradle". His "Ice-Nine" is a type of water molecule that solidifies at room temperature, which spreads its properties when it comes into contact with regular water. Worldwide catastrophe ensues when it falls into the ocean, solidifying most of the world's water.
3. The car that the Machine drove Finch to the airport while he was in San Jose, CA is a Tesla Model S semi-autonomous vehicle. Tesla developed an autopilot feature that allows the vehicle autonomously drive on roads without the driver ever touching the steering wheel.
4. The simulations the Machine shows to Finch are reminiscent of It's a Wonderful Life (1946). In the film, the main character is convinced he world would be a better place had he not been born. An angel shows him what the world would have been, helping him to realize his life did make a difference in the lives of others.
5. As the Analog Interface, Root had a cochlear implant in her right ear. The simulation Root wears a visible earpiece in her left ear.
6. NIPRNet is a Non-classified Internet Protocol (IP) Router Network, and is used only to transmit non-classified communications. SIPRNet is Secret Internet Protocol Router Network, and is used to transmit Confidential and Secret communications. JWICS is Joint Worldwide Intelligence Communications System, and is used to transmit Top Secret communications.
7. The ICE-9.exe virus password is "Dashwood." This is the last name of the lead characters in Jane Austen's novel Sense and Sensibility (1995), the novel Finch gave to Grace when they became engaged. It is also the book that Shaw is glancing at when Reese identifies Greer as the new number.

Return 0

1. "return 0" is usually the last command before the program quits. It means that the code has executed without errors.
2. The writers of the show originally planned to end the episode with the David Bowie song "Heroes", until composer Ramin Djawadi presented them an original piece he composed and they chose to use that instead.
3. Cameo: Jonathan Nolan, creator of the series and writer of the episode, can be seen on Times Square among the bystanders as Harold arrives.
4. Show creator Jonathan Nolan co-directed the scene with Finch in Times Square.
5. The USS Garner is a homage to actress Jennifer Garner who starred on the J.J. Abrams program Alias (2001)
6. At the end Shaw and Fusco say to each other "See you when I see you." and "Not if I see you first." These are also the last words spoken to each other by Chris and Gordie in the Stephen King movie Stand by Me (1986)
7. In one of the final shots, a glimpse to John's grave is shown. The first three letters of his real last name can be seen: "John Tal...".
8. The episode title refers to concepts in computer programming. In programming, a function is typically a block of code that calculates a numerical value and "returns" that value to the code that requested it; thus "return" is the command that exits the function. In the context of the overarching main function of a program (i.e. the function that is run at the start of the program), returning the specific value 0 will end the program and also indicate that the program has completed properly.The title could be interpreted in at least two ways: 1. The Machine's plan was executed successfully, destroying Samaritan and being reborn. 2. The completion of the show was satisfactory, and the story has reached its proper ending.
9. All four main characters' last lines are farewells. John says, "Goodbye, Harold". Harold says, "Goodbye" to The Machine. Shaw and Fusco say to each other "See you when I see you." and "Not if I see you first." Although Finch is seen at the end reconnecting with Grace, he does not say a single word.
10. Moments before Samaritan starts communicating with Finch in Times Square, a giant red eye appears on one of the big advertising screens and seems to look right at Finch.