"I can do that." 

Something presses ominously against the door. Lucy flicks the door open and then dives to the side so indestructible guy can deal with it. 

The indestructible guy deals with it and sees himself out. Is there anything in this hallway at the moment that he needs to kill.

There is lots of stuff in this hallway that's enthusiastic about trying to eat him!

Well, better him than some teenager! He floods the entire hallway with liquid nitrogen, not densely enough for anyone to have trouble breathing in their sleep.

Liquid nitrogen does for everything that's currently trying to consume his life essence! Further things hang back a little but start charging in once the liquid nitrogen is gone. 

He will try various liquified components of normal air mixture in the correct approximate ratios.

These work variously well at killing things! 

The rate of things-to-be-killed slows down any over the course of the night, but they sure do refuse to stop trying to kill him altogether.

Well, if they slow down enough, he can maybe conjure the complete works of that guy listed on the blueprint poster over there and see if any of it says WHAT THE FUUUUUCK.

Lucy opens the door at precisely 6:00 the next morning. 

"You're still alive! Come in, I don't want to have to try to explain you to my neighbors before I have any idea what's going on myself."

Cam goes in. "Thank you, don't mind if I do, can I get you breakfast or anything?"

"--If you can produce a breakfast that is definitely zero percent poisoned then yes."

"Why would I poison you?" he asks, handing her a plate of pancakes and bacon.

"--I mean, I'm not suggesting you would do it on purpose," she says, accepting the plate. "Where...did this come from, exactly? Do you have a spell that just summons food?"

"I can make arbitrary material objects? It didn't come from anywhere. It just exists now." He makes himself a plate of the same and digs in.

"You can what." She checks the plate for nasties just to be safe, then starts eating. "I admit that my affinity is bullshit, but that's insane."

"It's a thing my species can do, there's billions of us. I agree it's very cool."

"--And your species--exists in the Void?"

"That's one of the things people call it, yes."

"What else do people call it?" she asks, fascinated despite herself. 

"In English 'Hell' is most common."

"--Sorry, you're saying the Void is Hell???"

"Its reputation is greatly exaggerated."

"Can't be worse than a maw-mouth, I guess."

"I again don't know what that is. I tried to get some reading done overnight when the monsters slowed down but they didn't slow down much."

"They wouldn't have, no. A maw-mouth is a fleshy sack of mouths, eyes, and pseudopods. The best advice for dealing with them is to be somewhere else. The second-best advice is to die before it can get you. Unlike most mals, a maw-mouth won't kill you, and you do not want to become one of the sets of mouths and eyes. --You won't encounter any up here, though, they stay down in the graduation hall. Uh, that's the place where the Scholomance joins up with reality, and where mals can wiggle their way in, but there's more warding between the graduation hall and the rest of the school so only relatively little stuff gets up here."