Extremis (TV story)

 was the sixth episode of the tenth series of Doctor Who produced by BBC Wales.

Most notably, the episode revealed that was inside the vault beneath St Luke's University. It also explained how Nardole came to travel with the Doctor after the events of The Husbands of River Song.

The episode is also notable for being one of the few stories to have the Doctor not be a part of the events going on within the story; as Bill, Nardole and the Doctor himself never left Earth during the story, aside from the beginning, flashbacks with Missy and the end the whole episode was set in a virtual simulation with artificial versions of the Doctor, Bill and Nardole, with the Virtual Twelfth Doctor discovering an upcoming alien invasion.

Synopsis
The Vatican asks the Twelfth Doctor to investigate a mysterious book called the Veritas. All who read the Veritas immediately kill themselves. When a translation of the Veritas is leaked online, the Doctor must face up to the inevitable truth...

Plot
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Cast

 * The Doctor - Peter Capaldi
 * Bill - Pearl Mackie
 * Nardole - Matt Lucas
 * - Michelle Gomez
 * Moira - Jennifer Hennessy
 * Cardinal Angelo - Corrado Invernizzi
 * The Pope - Joseph Long
 * Penny - Ronke Adekoluejo
 * Rafando - Ivanno Jeremiah
 * Piero - Francesco Martino
 * Pentagon Woman - Alana Maria
 * Nicolas - Laurent Maurel
 * Monk - Jamie Hill
 * Voice of the Monk - Tim Bentinck

Crew
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Time Lords

 * Time Lords have two hearts and three brain stems.
 * One stipulation of the Fatality Index is that a death sentence of a Time Lord must be carried out by another Time Lord. That Time Lord must also swear an oath to guard the condemned's body for 1000 years in case of relapses.
 * The Doctor worries that, because he managed to temporarily "borrow" eyesight from his future self, his future regenerations might all be blind, or he might not regenerate at all.

People

 * Pope Benedict IX made a personal recommendation for the Doctor in 1045. He remembers Pope Benedict, and recalls, "I knew she was trouble, but she wove a spell with her castanets."
 * The Pope pays the Doctor a visit in the lecture hall.
 * The Pope is also known as the Bishop of Rome.
 * The virtual Doctor says that the Pope doesn't "zoom around in the Popemobile, surprising people".
 * An Italian newspaper brought a minor story known as "Colossal-Lotto" about a lottery winner by the name Harrison O'Shea in Milan written by Paolo Ferrera.
 * Virtual Bill brings Penny home on a date. Penny runs away after seeing the Pope in Bill's bedroom.
 * Virtual Bill thought that virtual Moira would be out with "Harry" tonight, who is actually named Howard.
 * The last emails sent before the translator kills himself were, chronologically, to Abramo Tognaccini (We have been tricked by the devil – in French), Daryn Mcloughlan (Pray for your family), Phil Bond (Pray for us all tonight), Franco Esposito (The world is not what we think – in French), Christina Tom (Farewell), Kevein Paters (Chapel Day), Albertina Ricci (Pray for us all – in French), Bill Pullman (Thursdays meeting), Peter Dukes (The devil's work has been done), Nicia Russo (We have been tricked), Michael Finch (Missed meeting), Stefan Anchorage (Farwell on this earth – in French), and, finally, four hours before death, to CERN European Organization for Nuclear Research, VERITAS, containing the translated text.
 * The President is lying dead in the Oval Office. News reports say he hasn't been seen for 12 hours.
 * In the real world, the Doctor tells Bill to talk to Penny.

Technology

 * A machine has been arranged to execute Missy.
 * The Doctor gets an email on his sonic sunglasses, which the virtual Doctor has sent, from within the Shadow World simulation.
 * The Doctor also uses his sonic sunglasses to scan people's data, as he cannot see them.
 * Data the Doctor can detect are:
 * Gender (including male and female)
 * Age (in years)
 * Height (in centimetres)
 * Weight (in pounds)
 * Heart rate (in BPM)
 * Temperature (in degrees Celsius)
 * He can also get a sense of the architecture around him, again using the sonic sunglasses as visual aid.
 * The Doctor employs a reading aid with circular Gallifreyan script on it, which he hopes will temporarily restore his sight. He confirms that it's deadly.
 * Bill notes that the Haereticum has WiFi, and the Doctor says of course it does; it's a library.
 * According to a plaque at CERN, its Large Hadron Collider, which was first tested on 10 September 2008, is the world's largest and most powerful particle accelerator. It has a diameter of 27 kilometres, and, to work, requires the magnets to be cooled at -271.3°C—a temperature colder than outer space. To achieve this, much of the accelerator is connected to a distribution system of liquid helium, to cool the magnets, as well as to other supply services.
 * The translator has a laptop computer.
 * He emails the translation to CERN.
 * The email provider bears resemblance with Protonmail, a mail-service founded in 2013 at the CERN.
 * The CERN employees all have TNT explosives wired under the canteen tables.
 * The countdown to destruction at CERN happens on a flatscreen TV.
 * A flatscreen is seen in the White House, as well.

Organisations

 * CERN is the largest particle physics laboratory on the planet.
 * The Pentagon is the headquarters of the United States Department of Defense, located in Arlington County, Virginia.

Religion

 * An early Christian sect managed to translate the Veritas before all committing suicide.
 * The Veritas is older than the Catholic Church itself.
 * Suicide is understood to be a mortal sin in Catholicism, leading one to hell.
 * The Pope hopes for God to help the Doctor on his quest.
 * Pope Benedict said that the Doctor was "more in need of confession than any man breathing", but when the offer was made, the Doctor replied "it would take too much time".
 * The Doctor says that religion is "designed to confuse the uninitiated", as Angelo says of the layout of the Haereticum.

Food and beverages

 * The man in the cage had been there a long time and eaten lots of food, bananas and sandwiches included. He also had coffee.
 * The CERN employees all drank all sorts of wines before the end. Chateau Cissac included.

Locations

 * A long time ago Nardole told the Doctor that he followed him from Darillium and that he has full permission from River Song to kick his arse.
 * Nardole tells Bill that the Vatican is in Rome, which is in Italy.
 * The Haereticum contains a cage with the Veritas locked inside.
 * A total blackout has occurred at the White House. The Doctor confronts a Monk in the Oval Office.

Weapons

 * Piero has a gun that he uses to kill himself.

Culture

 * Virtual Bill exclaims "Harry Potter!" upon seeing the Haereticum for the first time.
 * Virtual Nardole says that the Doctor and Angelo would be "wizard" at writing Christmas crackers, when, together, they say, "Truth in the heart of heresy" / "And death in the heart of truth".
 * Virtual Nardole relates holographic simulations, with holographic people to the holodeck on Star Trek, "or a really posh VR without a headset".
 * Virtual Nardole compares the simulation to Grand Theft Auto, and the virtual Doctor likens the inhabitants of the Shadow Earth finding out they are a simulation and committing suicide as a result to a hypothetical scenario in which "Super Mario realises he's inside a video game".
 * The Doctor mention Moby-Dick and the titular whale.
 * The Doctor owns a snakes and ladders game in the TARDIS.
 * Upon seeing the Monks, the Doctor pokes fun at the saying that no one looks good in the morning.
 * Many of the simulated people took the Shadow Test to confirm they were not real.

Story notes

 * The read-through on Extremis began on 23 November 2016, took a break for Christmas, and then wrapped up on 17 January 2017.

Ratings
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Filming locations
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Production errors

 * Outgoing emails on the laptop are shown, when in fact the inbox, rather than sent messages, is open on the left panel. Later, when the Doctor opens it again, the same messages appear, but now in sent.
 * The reflection of a cameraman can be seen on the TV at CERN, when the camera pans in on the bomb countdown just before detonation.

Continuity

 * Reference is made to Time Lords' binary vascular system, (TV: Spearhead from Space, et al.) and it is stated that they also have three brain stems.
 * Rafando mentions the tendencies of Time Lords to have relapses of life. (TV: Doctor Who)
 * Bill mentions how her attempts to change home didn't work out. (TV: Knock Knock)
 * Missy mentions "domestic bliss on Darillium", (TV: The Husbands of River Song) as "the word among the Daleks". (TV: The Witch's Familiar) Missy asks what happened, but is met with silence, and gives condolences for his loss. (TV: Silence in the Library / Forest of the Dead)
 * The Doctor is standing thoughtful in the lecture hall. (TV: The Pilot, Oxygen)
 * The Doctor is still experiencing blindness. He lost his sight in the vacuum of space, saving Bill's life. (TV: Oxygen)
 * River Song's diary is seen being used by Nardole, (TV: Silence in the Library et al.) from which he recites a passage from River about how the Doctor is a "madman in a box". (TV: The Eleventh Hour et al.)
 * The Doctor and Nardole discuss the Veritas with the Pope and Cardinal in his office. (TV: The Pilot, Thin Ice, Oxygen)
 * The Haereticum is a library of heretical and forbidden works maintained by the Vatican. Since his first incarnation, the Doctor has also been a patron of the Library of St John the Beheaded, a similar collection also established by the Vatican, which was hidden in London. (PROSE: All-Consuming Fire, White Darkness, Millennial Rites, The Empire of Glass, Dragons' Wrath; AUDIO: Zagreus, No Place Like Home.)
 * Virtual Moira is going to the pub. (TV: The Pilot)
 * The Doctor is brandishing a new sonic screwdriver. His previous sonic, of the same design, was destroyed in TV: Oxygen.
 * The Doctor promises to guard Missy "on my oath as a Time Lord of the Prydonian Chapter". (TV: The Deadly Assassin, PROSE: Lungbarrow) Spandrell once referred to the Doctor as a "Prydonian renegade, and mentioned "Prydonian vows". She said that "when a Prydonian forswears his birthright, there is nothing else he fears to lose." (TV: The Deadly Assassin)
 * Nardole calls the Doctor an idiot, to which the Doctor replies that everyone knows that. (TV: Death in Heaven)
 * A plaque at CERN reveals that the large Hadron Collider "first started up" on 10 September 2008. Jack Harkness was present, with his Torchwood Three team of Gwen, Ianto and Martha, when this first test opened a portal to another reality, through the LHC, and let out some neutron eaters. (AUDIO: Lost Souls)
 * The Third Doctor's companion Liz Shaw joined CERN after leaving UNIT in the 1970s. (PROSE: Country of the Blind)
 * The Doctor complains about the book Moby-Dick, and suggests it would help to be tied down to a chair, to get through it. The Seventh Doctor previously told Ace he tried over a hundred times, but could never get past the first ten pages. (PROSE: Sunday Afternoon, AD 848,988)
 * The virtual Doctor sits in the President's chair in a holographic recreation of the Oval Office. The Eleventh Doctor previously did just that in the real Oval Office. (TV: The Impossible Astronaut)
 * The virtual Doctor uses the sonic sunglasses to send a message. The Doctor used them to get out of an impasse before. (TV: Before the Flood) He also used them to summon reinforcements on Gallifrey. (TV: Hell Bent)
 * The Doctor was previously aided by a virtual copy of himself. (COMIC: A Life of Matter and Death)
 * Bill uses the word "wizard" to describe the Doctor. Donna Noble previously used the phrase in a similar manner, (TV: Turn Left) as did the Tenth Doctor. (TV: Journey's End)

DVD releases
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Blu-ray releases
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Digital releases
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