That which goes THUD in the night

So, in Nikki's last post she mentioned that we've gotten Annie into a toddler bed. So far things are going pretty well. Last night I was on duty though, which means that it was my turn to man the video monitor and be "on call" should there be issues. Anyway, I'm dead asleep and she wakes up and cries out because she's disoriented. This is normal because she's still getting used to the bed.
So, I go in and calm her down and she falls asleep with me rocking her. I lay her down on her bed and tiptoe back to my bed. I'm barely under the covers when I hear a massive THUD! Thinking that she's stomped out of bed and is charging for the door to reprimand me for leaving (she does this, mind you), I get up, without looking at the monitor and head for her room. Now, normally in this situation, she's waiting for me at her door and looking up at me waiting to get picked up. As I open the door this time though, there is no Annabelle. I tip toe into the room to figure out what is going on and find her sprawled on the floor (carpeted), next to her bed. He butt is in the air a bit, with her knees under her. Her arms are sprawled out a bit and her face is pressed to the floor, cheeks distorted from the additional weight shifting forward from being on her knees. Dead asleep.
Apparently she rolled out and fell into that God awful position with a resounding THUD and didn't even have the decency to wake up!
So, I pick her up like a complete rag doll, to which she doesn't respond, and plop her back into bed.
This was all at about 1:30am. She falls back to sleep, blissfully unaware of the drama she's caused. By now, I'm far too awake and, try though I might, never get back to sleep...
Oh, to be 2 and blissfully unaware once more...