Bus conductor (The Greatest Show in the Galaxy)

An android bus conductor on the planet Segonax, while it was built to be a bus conductor, the chief clown had it programmed to kill. It killed Flowerchild and was about to kill the Seventh Doctor, Ace, Captain Cook and Mags but the Doctor was able to disable it.

Later, the chief clown forced Bellboy to fix the bus conductor, and the robot clowns took it back to the bus. Kingpin and Ace went to collect something hidden aboard the bus and the bus conductor tried to kill them, but at that point Kingpin regained his memory and remembered how to destroy it.

Kingpin instructed Ace to press a button on the bus conductor's head. Ace did so and got clear only seconds before the bus conductor blew up. (TV: The Greatest Show in the Galaxy)