Alex changes into a stream of smoke and waits for him to return.
And Cam comes back. "She's out. This isn't long-term sustainable, though, I imagine someone will notice her missing. What can you tell me about local astronomy - moon, planets, that sort of thing?"
Alex returns to human form and says, "I don't know the moon's phase right now, but it takes thirty days to complete a cycle. I also don't know much about the planets, none of my masters were ever interested in them."
"Thirty day moon phase cycle doesn't sound far wrong. Okay, do you know where I could fly into the air in a small self-propelled vehicle?"
"They exist, but it would be hard to get one. Can't you fly?"
"...I am planning to make the vehicle out of nothing, not steal it, and I am planning to fly to the moon."
"That's not possible. You'll die."
"Heat, cold, lack of air, exhaustion. Do you have any idea how far it is?"
Cam laughs. "Oh, I thought you were going to tell me that this version of the moon was surrounded by a nimbus of arcane energy, or something. I'm going to make a really nice vehicle that is intended for earth-to-moon trips, okay? And I can't die of any of the listed things."
"Be careful. Many demons have died trying to reach the moon. If you die will my master wake up?"
"...Look. I'm indestructible. I can be harmed to the level of 'slightly uncomfortable' and no farther by all conventional means of harm. I'm a little antsy about magical harm, which is why I wanted a safe test with your little fireball, but flying to the moon is nothing. If there turns out to be a nimbus of arcane energy, eventually she'll wake up, but she'll be somewhere between here and the moon with no demon to make food for her, which I imagine would be dreadfully inconvenient, right?"
"Are you taking her with you?"
"Yeah. I mean, if you'd rather I put her someplace more convenient to you I'm open to suggestions, it just seems likely that nobody is using the moon here and she will have trouble getting down if I do miss a dose of her coma drugs."
"Is that why you're going to the moon? It seems rather difficult. It will be a while before anyone thinks to look for her, and surely the bottom of the ocean would be just as effective."
"I have much less practice with going to the bottoms of oceans."
"Your world must be very strange."
"I don't think of it that way, but probably. So my plan is to put her on the moon, set her up to continue being comatose and fed without my intervention for months, and come back down to get a crash course in what this world is like."
"Or you could leave her in the basement and lock the door. You really don't need to go to the moon."
"Aw, but then I won't have a really good excuse to continue to Mars and terraform it. Fine, fine, if you think she'll be hidden enough that way. Can you carry her? Bit much for me."
He continues to the magician study, hefts her his shoulder, and starts down the stairs.
"Mars is - presuming this is an Earthlike solar system, which I have not fully confirmed - a planet, about the same size as Earth, but uninhabitable. I have always wanted to make it habitable!"
Alex dumps the magician unceremoniously onto the floor of the basement, then slams the door and grins.
"Cool factor. In case something happens to Earth. Thriving scientific research, athletics, and musical theater. I still need to set her up with a nutritional IV if I don't want to have to visit her every few hours." Cam re-opens the door.
Alex stares at him, "What? In case something happens to Earth? Is there something that can destroy an entire world?"