That's a really funny smell.
It's almost human but not quite, and it's nowhere near hybrid or wolf. A new species, or an unusual witch? He goes check it out.
"I mean, how do you know that?"
"It's in the definition. Don't crawl into it. But it can't come get you because it's nothing."
"I'm not afraid it's gonna come get me, I'm afraid we might accidentally fall into it!"
"Void doesn't kill you instantly. The TARDIS would pull us out."
"It's worked so far. And besides, I bet you'd survive longer than me."
"Yes but I'm more worried about my mate."
"If you're that worried you can go hide in the TARDIS."
"I don't know how worried I should be, is all."
"Fine, then. Let's move on."
There are windows. Some open, some don't.
There's a snow covered forest, silent and still and beautiful. There's a city full of shining towers that are too tall and too thin. There's a desert, empty even of cactuses. There's a quaint village with sheep grazing in the central green.
No matter which window they look out of or how far they climb, there are never any people.
It gets tiring real fast.
The Master eventually opens one of the windows that can be opened, one leading to a snowy forest with a vague, foreboding castle in the distance and starts to climb out.
Out they go! Castle looks cool.
The TARDIS catches them.
"Aww, were we going to die?"
"Died, no. Broken multiple bones, yes."
"I could've fixed that!"
"I think she's trying to teach me a lesson on the existence of caution."
"Please don't get yourself killed, love, I can't bring people back from the dead."