Monster was alright.
It kept you guessing.
I guessed wrong, and thought until the end that it was some sort of telepathic parasite. When it was about to kill the professor and he took his glasses off, I was expecting his final words to be a shocked declaration that the mummy was still in focus - thus showing that he wasn't seeing it with his eyes.
I notice the Doctor being very calm and unaffected by the lack of air at the end. Either the writers just wanted to show him still remaining in control under pressure, or they remembered that his alien physiology has already been established as capable of surviving for a short time in vacuum.