Continuity mistake: As the Master escapes from Axos, he kills the UNIT soldier standing guard outside, whose beret falls off as he slumps to the ground. Cut to the Master standing over the corpse, and the missing beret instantly replaces itself on the head of the corpse.
The Daemons - S8-E5
Continuity mistake: The hoofmarks seen by both Yeats and Benton from the helicopter appear to be huge when seen from the air. Yet, when the helicopter lands, the hoofmarks are suddenly much, much smaller.
The Daemons - S8-E5
Continuity mistake: After completing the third summoning ritual, the Master turns towards the spot where Azal is about to appear. He has his arms lowered and Jo is stood to his left. In the next shot his arms are up, and Jo has moved to being in front of him.
The Daemons - S8-E5
Continuity mistake: In part one, watch for the continuity error when Miss Hawthorne turns to face the policeman: her cape appears and disappears from around her shoulders from shot to shot.
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 ★