Genesis of the Daleks - S12-E4
Continuity mistake: When Sarah falls from the scaffolding, a plank of wood saves her from death. Trouble is, she fell a foot from the outside of the scaffolding and most of the plank was inside the scaffolding, therefore her feet would have hit it and she could only have landed with her head pointing inwards. But when we see her, her head is pointing outwards. (00:01:25)
Genesis of the Daleks - S12-E4
Revealing mistake: During the Doctor's early conversation with the Time Lord, there is fog swirling around them. When the Doctor agrees to take on the mission, it suddenly appears very concentrated around the tip of the rocks behind them, as if generated from a source behind the rocks. Normal fog would not do this, and it's clear that dry ice was used as the fog effect (DVD commentary confirms this). (00:02:45)
Genesis of the Daleks - S12-E4
Visible crew/equipment: Just after The Daleks move past the Doctor and the female Thal soldier in the corridor, a piece of lighting equipment is reflected on the wall behind her. (00:08:00)
Genesis of the Daleks - S12-E4
Continuity mistake: When the Doctor drops the time ring, it lands very close to the wall. When he picks it up later, however, it's in the middle of the corridor. (00:09:40)
Genesis of the Daleks - S12-E4
Revealing mistake: When Ronson is killed by The Daleks, you can see Ronson reacting a little too soon to the Dalek laser. (00:14:40)
Genesis of the Daleks - S12-E4
Visible crew/equipment: In episode 1, when General Ravon is being held at gunpoint and he says 'they won't last much longer', the shadow of the boom pole is moving on the door behind him. (00:15:15)
Genesis of the Daleks - S12-E4
Revealing mistake: In episode 6, when the Thals detonate the charges, smoke is seen coming through the door before the detonator is pressed down. (00:19:40)
Genesis of the Daleks - S12-E4
Continuity mistake: In episode 6, when the lead Dalek is saying 'Pity? I have no understanding of the word' the lights on the top of its dome stop working. They start working again in the following shot. (00:21:00)
Genesis of the Daleks - S12-E4
Continuity mistake: The Doctor's big brown overcoat was taken by the regular Kaled army in episode one and disappeared. In episode six, the Doctor goes into the incubator room and comes out with his brown overcoat magically restored.
Genesis of the Daleks - S12-E4
Revealing mistake: Whenever there's a close-up of Davros, it's very easy to see that there's a gap around his mouth where the mask should blend in with the actor's face, but doesn't. This mistake was rectified, incidentally, in Davros' next appearance in "Destiny of the Daleks."
Genesis of the Daleks - S12-E4
Continuity mistake: At the very beginning, Sarah comments to the Doctor that they haven't returned to "the beacon." When they were last on Nerva - in "The Ark in Space" - it was referred to as a space station. It doesn't become Nerva beacon until the next episode.
Genesis of the Daleks - S12-E4
Deliberate mistake: Chief of Security Nyder wears an iron cross on his uniform which mysteriously disappears in episode 3 - apparently the producers felt it was too close a reference to Nazism so it was removed from the show. (Source: DVD commentary).
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 ★