Bubblecar said:

dv said:

Castrovalva

The 5th Doctor is having a rough regeneration and needs to spend time isolated from outside signals. The Master captures Adric to build a trap, while Tegan and Nyssa try to keep the Doctor safe. Escherian geometry ensues.

I’ve seen this one several times and know it well, particularly remembering the impossible collapsing geometry of Castrovalva, the threat of the Big Bang, the successive clues about the trap. Recursion is a theme.
The 5th Doctor does some brief mimicry of the 1st and 2nd doctors as he wanders around.

They really did have Tony Ainley laugh a lot.

TEGAN: “What’s a Zero Room anyway? The Doctor said something about null interfaces.”
NYSSA: “ I suppose it’s some sort of neutral environment. An isolated space cut off from the rest of the universe.”
TEGAN: “He should’ve told me that’s what he wanted. I could’ve shown him Brisbane.”

Apparently Ainley loved the role so much he played the Master in his private life.

>Ainley’s great love of the role is often cited in documentaries and DVD commentaries. Script editor Eric Saward claimed that he introduced himself over the phone by saying “This is the Master” and then would laugh. In the commentary and documentary for The Mark of the Rani, both Colin Baker and Kate O’Mara say that “He only ever wanted to play the Master.” Baker remarked that he could afford this luxury because he had built up a private income by the mid-1980s and had inherited a considerable sum of money from his father. In “Cat Flap: Making of Survival”, Sylvester McCoy confirms that all he ever wanted to be was the Master, and he kept his role active, even when not on set. “He was as scary off camera as he was on it.”

His last turn in the role was in the game Destiny of the Doctors

https://youtu.be/eTuha6P9SVo?si=TKijEEsPbq7t2Fqt

I might see if I can find an emulated version