"Oxygen" is the fifth episode of the tenth series of the British science fiction television series Doctor Who. It was written by Jamie Mathieson and broadcast on 13 May 2017 on BBC One.
The Doctor (Peter Capaldi), Bill Potts (Pearl Mackie) and Nardole (Matt Lucas) investigate a space station after receiving a distress call sent by it, but find that the station is infested with a crew of walking dead. The trio need to base their plans on how much oxygen they have left, when they find themselves in a seemingly hopeless situation.
Synopsis
The Twelfth Doctor, Bill and an angry Nardole travel in the TARDIS to follow a distress call to a deep-space mining station. When the TARDIS is jettisoned by the station's computers, the trio are forced to wear "smartsuits", robotic spacesuits capable of independent operation tied to the station. The suits are also the only source of oxygen, as the mining company does not provide an oxygen atmosphere inside the station, and every activity is measured in breaths. The surviving crew warn them that some suits have received instructions to "deactivate" their "organic components", killing the wearer via an electrical discharge but remaining autonomous. This signal can be carried by touch, which has caused most of the crew to be turned into zombies, enslaved to the suits' programming. The Doctor and the others plan to walk outside the station to an uncompleted portion not updated in the computer systems to hide. Bill's suit malfunctions during depressurisation and forces her to remove her helmet. To save her, the Doctor gives her his helmet as they spacewalk. He survives the vacuum of space, but has gone blind from the ordeal.
The computer discovers their location, but as they flee, Bill's suit again malfunctions and will not move, nor will it allow the others to carry it or release her. The Doctor leaves her behind, assuring her she will not die. She is, however, electrocuted when the zombies touch her. The Doctor reveals the limit of breaths is an algorithm to stop people "wasting" oxygen, part of the company's automated profit-making system; killing the wearers was just the logical endpoint of corporate profit over human life. He hacks the station's systems to cause the station to self-destruct if they are killed, and convinces the others this is a "good death" and revenge against the corporation. The computers recognise this threat to corporate profits and recalculate the suits' programming, and the zombies turn over their oxygen supplies to the survivors. The Doctor then revives Bill, knowing that her malfunctioning suit did not have enough power to lethally shock her.
The TARDIS is recovered, and they drop the survivors off at their head office to confront the company; the Doctor notes there was a revolution six months later. Nardole restores the Doctor's eyes, but when they return to the university and Bill departs, the Doctor reveals that he "can't look at anything ever again. I'm still blind".
Continuity
The Doctor tricks Nardole into believing that removing a fluid link will disable the TARDIS, when in fact it does not. In the 1963 story The Daleks, the First Doctor does the same thing to Ian Chesterton, forcing them to investigate a Dalek city to recover the materials needed to fix it.
Outside references
The episode opens with the Doctor saying "Space, the final frontier". This is the classic opening in the title sequence of the original Star Trek science fiction television series, which ran from 1966 to 1969.
The Doctor quotes 1 Corinthians 15:55 when he says "Death, where is thy sting?"
Production
The read-through for "Oxygen" took place on 12 October 2016. The episode was filmed as part of the fourth production block alongside the tenth episode of the series, "The Eaters of Light". Shooting began on 17 October and ended on 18 November 2016.
In his newsletter, Jamie Mathieson revealed that "Oxygen" was originally intended as a prequel to his 2014 episode "Mummy on the Orient Express". In earlier drafts, Kline, a corporate representative, appears on a monitor to offer the characters promotions and stock options if they will spare the ship. Recognising Kline's voice, the Doctor takes the crew to safety by TARDIS, destroying the ship as they leave. It is revealed that the company behind the mining station will one day have a subsidiary specialising in analysing ancient weaponry, and that Kline will be fired as a result of his fumbling the negotiation, living on only as the voice of the company computer, Gus.
The assistant director for the series, Lauren Pate, plays the student who questions the Doctor in the opening scenes.