Paradise Towers two elderly residents ("rezzies") live. Tilda and Tabby explain that all the able-bodied men left the Towers to fight a war, leaving behind only children and the elderly. The only other man still loose in the Towers is Pex, a would-be hero, who appoints himself Mel's guardian. At the Caretaker control centre, the Doctor meets the Chief Caretaker, who greets him as the Great Architect, designer of Paradise Towers, and then promptly calls for him to be killed The Doctor cites an imaginary rule from the Caretakers' manual, confusing them enough to make his escape. Mel and Pex meanwhile have
The Doctor (Doctor Who) planet is protected. The Atraxi then shows 10 images, one of each Doctor from the first to the tenth, with the eleventh walking through the image of the tenth at the end. This is confirmed in the episode "The Lodger", when the Doctor, explaining to Craig who and what he is, points at his face and says, "Eleventh." Because each new Doctor is different from his previous incarnations, how their personalities interact varies when two or more different incarnations encounter each other. "Time Crash" featured Peter Davison returning as the Fifth Doctor. This event is explained as occurring due to