Sadde's running.
Not for any particular reason, just because it's faster. He's been meaning to go to one of the capitals for a bit and now, he supposes, is as good a time as any.
And eventually he's not running anymore, because he's close enough to civilisation that someone might spot him. Not that he wouldn't be able to notice them by scent before they saw him, but still. And as he makes his way to the Norway capital at this more leisurely pace, he notices the tiny, shiny key. He walks towards it and picks it up and immediately notices just how magic it is. He can tell by the way the key feels like things, and different things depending on where it is.
He verifies that what the key feels like is consistent in absolute location by waving it around a bit and seeing that the same place always feels the same. "Huh," he murmurs to himself.
He straightens up and thinks. The first obvious thing to try is seeing whether it opens any doors—a universal skeleton key sounds like the kind of thing a magical key could be—but the second obvious thing can be tested right there and then. He pushes the key into thin air with some purpose, as if he wanted to unlock an invisible door, and then turns it, et voilà, the faintest of door-shaped outlines appears before him.
He locks the door, and it disappears. Unlocks it again, and there it is. So he pulls it open and sees—
He locks the door, then tries again, and there a new door appears. He opens to reveal the sunset over a desert. "'Parently. Annndd it just occurred to me that I could've summoned you before we left your place."
"Oh well. Um. Okay, so, basically no experimental results regarding the portal from my world, some experimental results about intersecting portals." He locks the latest one. "That still leaves the possibility that someone else could come from my world and suffer unpleasantness."
"Yeah. I can put a tree there, but someone might notice it's out of place and get rid of it."
"Then someone will definitely notice it's out of place and remove it. Demons are pretty casual about destruction of property, it's not like I couldn't put whatever it was somewhere else."
"Could you maybe leave a hidden camera filming the place or something? I mean I'm not sure what good that'd do unless you had really good AI or image processing that could notice when a magical portal is opened..."
"Yeah, I can do that. We don't have legit AI but I can make something notice if anybody appears without having been somewhere else in frame before." Cam goes up to an in-place tree and puts a wee camera hiding in it, pointing at the location of the portal.
"I don't think so, our next step in testing was trying summoning across universes, though I have the feeling that might work similarly to dismissing across universes."
And Sadde opens a door that he knows opens more-or-less to ground level on the other side—a plateau of stone—and goes through with paper and an almost complete circle.
After about two seconds Sadde lets go and clears his throat. "Oops," he says.
"So, is casual affection which does not involve superglue and/or magnets something that I can unlock after week six, or what?"
"It, er, should be fine from now on, I think. I'm out of practice with completely new emotions hijacking my brain, just need to get used to them."