I think that Bib, and others, could have survived the "sinking" of Jabba's sail barge. While it's been quite a while since I've last watched Jedi, I know for a fact that it didn't just blow up out of the blue. I seem to recall there being a lot of panic aboard it during the whole battle scene and the sail barge eventually crashing. But I seem to recall it going down fairly gradually and likely with enough time for the quick witted or not quite 100% loyal enough to down with their boss to jump ship; you know, the whole it's easier to beg for forgiveness than to ask for permission thing. I could see Bib running away to save his skin once Leia got the deck cannon to shoot at the barge and at the first indications that the barge was going down.