I was on Left 4 Dead going for the no being healed and no friendly fire achievements. I was in single player mode, so they were all AI (yeah, I know this was a big mistake now). So I'm going through each level of No Mercy slowly and carefully, and I get to the Finale on 80 Health left, no friendly fire. First Tank comes, I molotov and run, got boomed so I couldn't see, Tank slaps me before dying. Despite still having 40 Health left, Louis decides he wants to heal me, I get annoyed but figure I'll still get friendly fire so it wasn't a waste. Hellicopter turns up, I'm running up the ramp, gunning a couple of Zombies in my way, when Louis steps infront of me and I hear "Hey, watch it!"