If I only had one bullet and had to choose between a known enemy and a traitor...
@π²πΎππ2π«β΄πβ―π :confederatefl... i'd try to go for a collateral just like in popular videogame Call of Duty Modern Warfare @f2f9d8a3
Shoot the enemy. Beat the traitor to death with your gun.
I'd go and get two more bullets after I shot the traitor once, just to shoot him again and be sure.