Well, I guess there are worse ways for a rapscallion such as himself to spend a juicy bounty than hanging around a mob boss' hacienda, banging all the dancer party galls. And as to why he doesn't stay out of the fight and flies into a goofy death - well, I guess he doesn't believe this jedi guy to be all that big of a deal and simply wants to protect his investments by protecting one of his best-paying employers. And he is going to a public execution, which is undoubtedly a fun event for folks such as himself, aboard a luxurious pleasure barge, so he probably had a few drinks, maybe snorted some space-coke, so it makes him a bit overconfident and it doesn't exactly help with his jet pack driving abilities :-D