A teleport bracelet was owned by the Doctor who stole it from Android Assassins who had captured him.
It had lost its power to teleport, but as the Doctor was nano-seconds from getting killed, he channelled their blasts of energy meant to kill him into his sonic screwdriver and into himself, and before it could kill him, used the teleporter that had recharged by their blasts to teleport away, and saving his own life. (TV: The Witch's Familiar)
Behind the scenes
- Although this was an earlier incarnation of the Doctor, the viewers were given the flashback with the Twelfth Doctor, although brief glimpses of the Fourth Doctor and the First Doctor were seen.
- Missy told this story to Clara Oswald, giving an in-universe explanation for the Doctor shown being the Twelfth, as it didn't matter to her, as they were all the Doctor to her. She therefore told Clara to just imagine "the eyebrows" (Twelfth Doctor).