The Talons of Weng-Chiang - S14-E6
Continuity mistake: When the Doctor smashes the crystal lattice on the floor, the deactivated Mr. Sin flinches.
Continuity mistake: When Palmerdale wakes Harker up and asks him if he can use the telegraph, Harker answers him, then asks him to repeat the question, then answers again.
Continuity mistake: In episode 4, Skinsale is murdered by the Rutan on the stairs right outside the crew room but later in the episode when the Doctor and Leela runs down the same stairs, Skinsale's body is not there.
Continuity mistake: In episode three, the readout strip dangling from K-9's mouth shortens between when he shoots the infected crewman and shoot Leela.
Continuity mistake: Lowe's "frozen" makeup changes between when he emerges from the freezer and when Leela brings him a cup of coffee.
Continuity mistake: The countdown clock in Marius' lab speeds up and slows down as needed for the plot.
Continuity mistake: The TARDIS is missing its light the first time it's seen.
Continuity mistake: In the opening TARDIS scene, after the TARDIS lurches from the time scanner, the Doctor's hat rack can be seen standing upright. Then Leela picks it up in the next scene.
Continuity mistake: After shooting the two guards near the beginning of episode three, K-9's nose blaster retracts twice - one in close-up, once in medium shot.
Continuity mistake: The Gatherer gleefully states that being on the roof is a fine of 500 talmars. Later, Cordo says it is 5 talmars.
Underworld - S15-E5
Continuity mistake: When the Doctor races out of the R1C with the fission bombs in episode four, Leela follows, carrying a shield gun. She steps into the cave and is only holding her knife. Later, she has her shield gun back.
Continuity mistake: When the Doctor shoots Stor with the De-Mat Gun, the flash starts on Stor's left-hand side, engulfs him, then jumps substantially to the right before whiting out the frame.
Continuity mistake: The Doctor has his scarf when he first meets with the Vardans. When he returns to the TARDIS, it is on the coat rack.
Continuity mistake: K-9 looks slightly different in the scene in which he's spinning inside the TARDIS: notice the pattern on his collar.
Continuity mistake: After the Doctor helps Romana over the cliff, the stock footage of a sun setting over a calm sea does not come close to matching the total darkness and stormy seas in previous shots.
Continuity mistake: During Kroll's attack on the refinery, several pieces of the refinery get broken off and then reappear in subsequent shots.
The Armageddon Factor - S16-E6
Continuity mistake: In episode 2, just after K-9 begins blasting the door, look behind Romana and notice that you can see the TARDIS - which supposedly left in the previous scene.
Continuity mistake: When the Count's henchmen come into the café to get the Doctor, Romana and Duggan, they usher them all out at gunpoint. When you see them in the location filming in Paris, Duggan's not there...but back at the Count's place (in the studio in London) he's reappeared.
Continuity mistake: In "The Ribos Operation", Romana stated that her age was 'nearly 140' (presumably Earth years, although this is never confirmed). However, in the later story "City of Death", Romana says that she is '125 years old'.
Continuity mistake: When the Doctor finds the vraxoin vial in episode 1, he puts it in his right coat pocket, from where it is then removed by Stott. However, at the end of episode 2, Costa's scanner finds vraxoin traces in the Doctor's LEFT coat pocket.
Answer: TARDISes are generally available for properly authorised use on Gallifrey; they're not usually assigned to a particular Timelord on a long-term basis. The Doctor stole his when he left his homeworld.
Tailkinker ★