So basically after picking the first one the mafia just sit around and hope that they aren't hit? I guess they try to keep the gunslinger from hitting themselves.
Yes. They can just sit around, if they'd like, or they can build cases on innocents, twist statements, plant doubts, etc. (all the fun stuff that mafium like to do) in order to try to direct the hit away from themselves.
The mafia doesn't get hits this game, but keep in mind that their win condition isn't as difficult either. They only need to equal the number of townies minus the gunslinger. So with the initial 8 v 4, three consecutive misfires at the beginning equals a mafia victory.... (5 townies minus 1 gunslinger vs. 4 mafia).