[quote=Vash]
He's on a crime planet run by crime people! He's no doubt skilled in many areas of crime expertise!Come on! Just look at the doctor from Team Fortress 2! That guy kills people for a living AND heals people!
[/quote]

He's actually not really a criminal. He does his best to run a legitimate operation most of the time. The shadiest thing about it is that he doesn't ask people questions, even if they come in with riddled with bullets. :/

EDIT: Well, there is also the whole 'practicing medicine without a license' thing, but at least he's up front about it with people.