- Actor-Inspired Element: It was Sylvester McCoy's idea to have a Cats poster in the youth club.
- Awesome, Dear Boy: Rona Munro approached script editor Andrew Cartmel at a BBC scriptwriting workshop and said that she'd "kill to write for Doctor Who".
- DVD Commentary: Along with the normal commentary on the DVD, the third episode also was commentated on by a group of fans who won a contest in Doctor Who Magazine.
- Executive Veto: Midge's unexplained death is because BBC executives considered the original scripted fate for him (after he loses the motorbike-chicken game with the Doctor, the Master has the other cheetah-infected boys tear him apart for showing weakness) unacceptably gruesome.
- Stunt Casting: Alternative comedians Hale and Pace feature prominently as staff in a corner shop.
- What Could Have Been:
- According to Andrew Cartmel, the initial draft of the script did not feature the Master at all, and he was introduced because John Nathan-Turner wanted at least one story in the season to feature a "name" villain. A broadly positive example of Executive Meddling, as the Master's role in the story is plausible and in character, and what turned out to be his final old school appearance reversed much of the Villain Decay he had experienced in the previous couple of appearances.
- Sgt. Paterson was originally a policeman (and it was in this capacity that he investigated complaints of the Doctor's behaviour), but this was changed as the producer did not want a negative portrayal of a policeman.
- Rona Munro's original conception of the Cheetah People had been as basically human creatures, albeit with cat-like eyes and fangs, and perhaps a vaguely feline mouth.
- In the original script, Ace was to burn Karra on a funeral pyre, connecting with her pyromania.
- Originally, the Doctor was to transport both himself and the Master back to Perivale after their climactic duel on the planet of the Cheetah People. The Master would then confront the Doctor as to his true nature, accusing him of being something other than a Time Lord. The Doctor admits that he has evolved is not "just" a Time Lord, before describing himself as "multi-talented". The Master then uses a Kitling lurking nearby to escape. John Nathan-Turner felt that this scene was too explicit in casting doubt on the Doctor's past, and had it excised, with the Doctor now returning to Earth alone.
- The motorcycle duel between the Doctor and Midge was to have taken place in a disused lot or building site thus better explaining the seemingly miraculous appearance of the sofa on which the Doctor lands.
- Word of Gay: Rona Munro said that the lesbian subtext between Ace and Karra was deliberate.
- Working Title: Cat-Flap, Blood Hunt and The Survival. The first title is Hilarious in Hindsight because when the show came back some 16 years later, one of the first things the Doctor did was nearly stick his head through a cat-flap.
Trivia / Doctor Who S26 E4 "Survival"