The Trial of a Time Lord 5-8 (aka Mindwarp) - S23-E2
Continuity mistake: When Kiv wakes up in Peri's body, (s)he orders Crozier to kill the body Kiv was using before. Crozier responds that it's already dead, but in the previous shot the old body could be seen breathing.
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 ★