He feels an open summons and lets it grab him -
"Right, but do you really want to learn magic from two drunk guys who are careless enough to let you convince them to teach you magic while they're still drunk? How do I even know you're telling the truth about the black holes? I don't know a damn thing about your magic."
"I didn't say how about you start giving me lessons right now, I was wondering why it was such an obvious bad idea. I'm not going to even entertain the idea of me demo-ing the black hole on a planet's surface but if you want something else made I'll consider it."
"Anyway, what do you mean, accomplish?"
"Arbitrary nonmagical matter includes, like, the ability to patch your ozone layer, I can't remember if that's known to be a problem yet? It's a problem later. My Earth, anyway. There's things I can't do, though, even with my sci-fi gadgets from the time travel part, so maybe magic could make me more well-rounded as an ozone-layer-patcher-errant."
"...I can't even think about this right now," says Ripper. "If you want to prove you can make things, you could make me another guitar."
"You want a fancy futuristic guitar or one like you've got?"
"If you can make me a fancy future guitar, make me a fancy future guitar!"
And lo, there is a fancy futuristic electric guitar, very sleekly built. Cam hands it over.
"It's got its own amp in it, so don't turn that dial on the end too far unless you want to deafen the entire block."
"Do you two need to get a room?" says Rayne.
He starts peeling up the masking tape that holds the circle.
Rayne looks at him suspiciously, then decides that this qualifies as cleaning and is therefore acceptable. Ripper is much too busy with his shiny new guitar to take particular notice.
Cam does some general tidying, although not with much efficiency. He's mostly casing the place for hints about the world he's landed in.
Books, guitars, a broken coffee table that he may safely assume was the victim of drunken shenanigans of some kind. Various empty bottles, together comprising an excellent education in local cheap alcohol.
Cam can't heal the table as seamlessly as an angel could, but with a firmly attached layer of intervening wood knitting the broken parts together he can do a passable job. It looks pretty much like a crappy apartment in the First World just before the turn of the millennium ought to look. Except for the booklist, maybe.
The booklist is a little weird. There are other books on magic, although none of them are about summoning demons in particular.
Cam investigates a book on magic.
This is enough to distract Ripper from his guitar. "Hey, what are you doing?"
"Reading your books. Would you rather I do this without your supervision by making my own duplicate copies somewhere else? Because I can do that if you're going to be a pill about it."
He rolls his eyes. "Fine, your funeral."
Read read read.
"Oh, what's the worst that could happen?" chirps Rayne. Ripper gives him a dirty look.
"What is merely reading this book liable to do to me?" inquires Cam, pausing in doing so.
"I set Ripper's hair on fire once," chirps Rayne.
"You did that on purpose," snarls Ripper.
"Yeah, but I didn't have to do much more than read a book to do it."