Floor 0000

Floor 0000, or the bridge, was the top floor, and flight deck, of a Mondasian colony ship.

When the colony ship almost fell into a black hole, each of the ship's floors was affected by time dilation. Located at the very top of the ship, time travelled slowest on Floor 0000 compared to any other floors on the ship; for example, two days and ten hours on Floor 0000 equated to over a thousand years on Floor 1056. (TV: World Enough and Time)

Layout
As the colony ship's flight deck, Floor 0000 featured several monitors, computers, keyboards and security cameras for piloting and maintaining the ship, as well as several chairs for the crew. The floor also featured several lift doors on one side, one of which was larger than the others and allowed for large equipment, such as an operating table, to be brought up from the lower floors. On the opposite side of the bridge, on slightly raised ground, were doors leading to other areas of the floor. The ceiling of the bridge itself had a large, hexagonal glass window. (TV: World Enough and Time)

The black hole
The colony ship was travelling from Mondas to pick up some colonists. (TV: World Enough and Time) On day 43 of its voyage, the ship almost fell into a black hole; the ship's janitor, Jorj, spilled coffee on a keyboard when the alarms sounded and wasted time cleaning the keyboard rather than alerting the rest of the crew, as he was the only person on the bridge at the time. The Captain sent a team of twenty engineers, including chief engineer Franq, (PROSE: Jorj) to Floor 1056 to reverse the rear thrusters, but because of the time dilation that the ship was experiencing due to the black hole, the team were unable to return to Floor 0000, and so remained on Floor 1056. (TV: World Enough and Time)

One day later on Floor 0000, life signs from the lower floors of the colony ship were detected; the Captain blamed Jorj, believing that he hadn't checked for stowaways before the ship left Mondas. The Captain sent another team down to the lower floors to investigate, but upon the return of the team's lift, several patients emerged, before capturing the remaining human crew members and taking them to Floor 1056.

The Doctor's arrival
Jorj broadcast a distress call and re-angled the security cameras. The next day, (PROSE: Jorj) the Twelfth Doctor's TARDIS landed on Floor 0000 in response to Jorj's distress call. , Bill Potts and Nardole emerged and were confronted by Jorj; when another group of patients began travelling to Floor 0000, Jorj shot Bill, the only human, in panic, despite the Doctor's attempt to diffuse the situation. The patients arrived and took Bill's severely-wounded body to Floor 1056, telling the Doctor that she would be "repaired", but not returned. The Doctor left a message in Bill's subconscious, telling her to "wait for [him]", and attempted to call her lift back, but was forced to calm Jorj down after being threatened by him. After explaining to Jorj that the colony ship was experiencing the effects of time dilation, the Doctor rendered Jorj unconscious before he, Nardole and Missy took a lift to Floor 1056 to rescue Bill, who had been watching footage of Floor 0000 from the hospital on Floor 1056 (TV: World Enough and Time) for ten years.

Later, Bill returned to Floor 0000 from Floor 0507 with the Doctor's heavily-wounded body and Heather, after the latter transformed Bill into a creature of sentient oil like herself. They brought the Doctor back to his TARDIS before leaving the colony ship. (TV: The Doctor Falls)

Sometime after, Jorj woke up, dismayed to see that the Doctor's TARDIS had gone. As he was finishing another blog of his experiences on the colony ship, an alarm alerted him to a huge explosion that occurred on Floor 0507, (PROSE: Jorj) caused by the Doctor attempting to destroy the army of Cybermen that the people of Floor 1056 had evolved into. (TV: The Doctor Falls) Jorj then observed some life signs moving up the ship, and hoped that, as a non-human, they would leave him alone. (PROSE: Jorj)