He's curled up in bed, dizzy with pain, barely coherent enough to wish he could pull it together and go get his meds, certainly not coherent enough to actually do it.
So he misses the moment of transition.
But ten or fifteen minutes in, when the storm finally subsides from his nerves, he opens his eyes and inhales and knows he isn't at home even before his blurred vision regains its focus. The air smells wrong. Wherever he is, it's not Thule.
After a few blinks, the view in front of him resolves into a sparkling waterfall, glittering gold in the sunlight. Literally gold. He sits up, carefully, wincing and scrunching his eyes shut when the movement sends a few final sparks of pain through his limbs; then he looks around. He is on the side of a mountain, surrounded by other mountains. The golden waterfall spills into a golden pond, from which a golden river continues on, winding downslope and out of sight.
Something about this whole scene looks... off. Something subtler than the gilded river. It looks unreal. He can't pinpoint exactly what's wrong with it, but it's - more like the descriptions of Fairyland he's read than like a real place on Earth. (Can't be a real place off Earth; you couldn't fit all this inside an arcology.)
Okay. He's been mysteriously transported to a strange mountainside in possibly-Fairyland. That's a thing that just happened. And either something was messing with his perceptions or it was done very subtly, because he notices when anyone grabs him or moves him around during an episode. It is very noticeable when that happens.
...might as well start by ruling a few things out. He finds a stick and a flat patch of dirt and draws a circle for the family fairy.