Revelation of the Daleks - S22-E6
Plot hole: The DJ fires the ultrasonic gun, to demonstrate it to Peri. The glass in the doors breaks. When The Daleks arrive the glass in the doors is unbroken. It then doesn't break the glass in the doors in any of the other times he fires the weapon.
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 ★