"The House that Jack built": Emma Peel is trapped in a computerized / automated house Professor Keller specially designed to drive her insane or drive her to commit suicide by gas chamber with absolutely no way to escape. The computer designed to answer her questions has a creepy monotonous voice also.
Tara King's situation in the climax of "The Curious Case of the Countless Clues": Steed phones her to warn her that two men are coming to kill her and that he's on his way, except that Tara's in a wheelchair due to a busted up ankle, and realizes that her back door is unlocked. Desperate, she climes up her stairs to lock the door, and just in time too.
In "The Last of the Cybernauts", Felix Kane survived the car crash and explosion at the beginning, but ended up badly disfigured and amputated of all limbs bar his right arm. To conceal his face, he wears creepy Uncanny Valley latex masks, and when his Cybernauts ploy falls apart, he decides to become a cyborg using Cybernaut spare parts, and comes very close to, if not killing, at least maiming and disfiguring Purdey, making his intent verbally clear while attacking her.