After entering your hospital room, the nurse did not realize you had shrunk as a side effect to the drugs you'd been administered earlier.
She always kicked off her shoes when in your room, so you knew you finally had a means of getting off the bed without splattering directly on the floor, hoping her shoes would cushion your fall.
You jumped off, and fell right into her shoe, not on top of it as planned ... perspective at those heights made you miscalculate the distance.
Seeing as you were "nowhere to be found", she didn't waste any time tidying up the room, and proceeded to put her shoes back on, for a long night's shift ... with you now stuck inside her shoe.