Not the mention the very fake, bright yellow plastic horns. And of course, the building had to have them too.
I didn't like the episode, though. Out of all of the ones from the 4th Doctor, I'd put that one near the bottom. But maybe a lot of that has to do with me finding the villain too ridiculous to take seriously. Not as bad as the villain from The Invisible Enemy, though (not to be confused with The Invisible Assassin)…I think I enjoyed that episode more even though the whole plot was really silly.
Conquest for the sake of conquest is par for the course in DW, it's pretty much all the Master ever seems to care about.