Insane sociopath?
So Vincent holds no regards toward human life, got it.
But what I mean by insane is, he's presumably being paid to do hits rather than for free right? So after he lost the briefcase with all his cash and ID, and later his boss doesn't trust him and sent guys to kill him. Why is he still so set on killing Annie?
Yeah imagine you killed her, now what? You can't go back to the club to collect, that'd be suicide, if he's just going to get on a plane and leave then surely he's not expecting the mob to honor their agreement and do a e-transfer. So he's practically risking his life in the end there to do a volunteer hitman job. Sure he doesn't care about who lives or dies, but you're exerting so much effort for an outcome that doesn't matter to you in the end now that your money incentive is gone. So why do it? Just go home.