pvp team setup

Currently I have

mutant ***
primarch ***
mutant **

and I'm wondering what I should put in my fourth slot. I have:

Cmdr Brodey (full auto)
Horde wall **** (meat shield)
Sieght (removes Alien Offense)
CRAP Lt * (stopping power)
Betty * (unstoppable force, but I don't have any more Bettys)
Dire Blades *** (hope that Alien Offense procs and get an extra hit with it)

Out of that list id choose bety. Even 1* if she procs she takes out nearly the entire team, bringing em down to like 20%