He jumps, yelps something that from tone and context is probably not a polite greeting, and looks around wildly.
He goes up to the edge of the ward and prods the invisible barrier cautiously, frowning at it as though he can somehow perceive its exact shape and location.
"I... see," he says. "As it happens I would actually rather not go back where I just was when you're done with me."
"Because I was in an empty building on a lifeless planet with no food, no water, and no other people in the universe as far as I could tell," he says. "Prospects seemed pretty grim."
"I was transported there mysteriously, unexpectedly, and suddenly by unknown forces."
"It's been that sort of a week," he says, grinning. "Anyway. I don't suppose you could let me stay in your nice universe which appears to contain multiple people? Or, alternately, send me back to my original universe?"
"I wonder if I can at least answer the question about what undoing the spell would do," he says, sitting down on the floor and looking contemplative.
"In a manner of speaking, I suppose. I have a form of magic that comes with a sensory or perceptual power unique to the individual user, and mine lets me understand functionality - systems, mechanisms, tools, that general class of thing."
He gazes abstractly at the floor and thinks aloud as he examines the spell.
"The barrier part's pretty straightforward but the summon part is a little trickier to get a look at, like trying to read something written on the back of my own head... huh, okay. Yeah, it would put me back precisely where it got me if reversed, which—um." He blinks and rocks back slightly, startled and alarmed. "Are you aware that trying to reverse this spell would kill you?"
"Lucky for me I didn't want to be back there anyway," he says. "Less lucky for you, admittedly."