Nyssa does not seem to be the least bit surprised by the drastic changes in her "father's" appearance.
Nyssa: Sonic projectors.
Tegan: What are they for?
Nyssa: They must be creating a temporary zone of stasis around the TARDIS. But I don't really understand their science.
Tegan: That goes double for me.
The Master: At last, Doctor... At last, I've cut you down to size.
The Master excels himself by obliterating a quarter of the entire universe, albeit unintentionally. Rather politely, no-one ever comments on this in later stories.