Sleepers wake up if they hear something, or if they're touched, or if their nap is timed and it times out. Being close to one w/o touching him has no effect.
I just went to test that out to be sure. Crouch walking near them will wake them up, though they won't say anything, they will just stand up. But, crouch creeping won't wake them up. So yeah, I was wrong, sorry about that.
When the sleeper fell through the floor, where exactly were you? Did he touch you as his wake-up animation played?
At first I also thought that might be the case, but if he touches me as he wakes up, he will just push me away. I went to reproduce it and managed to do it only once out of 20 tries. But that one time he fell through, it looked like something made him "slide" a bit during the waking sequence, but while still in the lying position.
EDIT: Found a way to reproduce it every time. Crouch-jump near his pillow during the waking sequence.
Edited by eqagunn, 18 October 2013 - 09:58 AM.