When they eat, like anything if you move it around to much or stress him out, he might regurge whatever he's eaten (thats happened to us once or twice)
You might still find him, we've had snakes get out here and there before (over the 5 years we've been doing it) and we've found them again, usually (as someone above mentioned) in a warm spot in the house, just be sure to look everywhere, even places you wouldnt think.
We had one of our olives get out and she had crawled into the dvd drawer under the telly (a warm spot) and then we had one of our other (much much bigger olives get out - so big that he actually lifted the top of the tank off, needless to say we moved him into someonething else lol) and he was actually in our bed!! Imagine my surpise when i went to crawl into bed that night haha!!

I really hope you guys find him, coz as sad as it is, most people would kill him