He doesn't notice the door opening until two seconds after it's opened, and realizes one second after Kate is standing there that she's standing there, blinking at him.

"Jeez-!"

In three seconds, the mirror clatters on the vanity table, pants abruptly get yanked up (the chafe), and a shin gets banged on the edge of the bathtub.

"Ow, ow ow ow shit-- Kate!"

He almost trips over his own feet getting to her on the floor, but fortunately he doesn't fall on her. They've done more than enough falling between them already, thankyouverymuch.

Kneeling, he hovers over her, his hand on her cheek. "Kate? You alright? Jeezus, I'm sorry!"