most people will tell you- you should never take all the strings off of a guitar at the same time. bad idea. think about it- all that tension (which is being countered by the truss rod), suddenly is gone. now the truss rod is doing it's thing with NO counter resistance from the strings. is it going to destroy your guitar? not likely but it could offset (no pun intended) what was a perfectly good setup before all the strings came off. that said, 5 minutes w/all the strings off is one thing, leaving them off for extended amounts of time (days? weeks?) is a very bad idea.
regarding the bridge falling off- that's what they do. slip it back on and restring it. hopefully you'll be able to tell if you've got it back on in the right direction, otherwise your intonation is going to be all messed up. if you don't know how to tell, GUESS. you've got a 50/50 chance of getting it right. good luck.
