The Professor's TARDIS

Shaped like a pair of doors, most commonly attached to nearby walls, the Professor's TARDIS is classiffied as a WarTARDIS, and comes equipped with weaponry capable of locking an entire region of space from all time travel. This weapon is a sort of mini-timelock, preventing temporal movement within several spatial light years.

During the course of the Gallifrey 5 series, the WarTARDIS was equipped with an enormous blue cannon capable of drawing power from a number of sources and able to destroy large areas with its blasts.