From the looks of the trailer, the situation and V's demeanor shows that he & Jackie went in guns blazing without much preparation, thought or foresight of the consequences. Even after the gunfight, the problems don't end there.
Jackie died, and things went south with Dexter, T Bug, and killed any future opportunity V had at working with them.
In this scenario, V is actually the one in the wrong, not Dexter. After getting a friend killed and Dexter turned on V for putting himself and associates in further danger. Really breaks that wall of good vs evil and boils down to choices on a bigger scale. I'd be pissed off too for V acting the way he did, selfish and wreckless only looking for the money.
A game with a moral code?
Awesome.