Sjakihata can verify this one... I was playing America's Army, on MOUT McKenna. I worked out that the last surviving Opfor must be in a specific building, so I heft my scavenged RPK and cautiously make my way in. Carefully checking around the corners once inside, I see a door opening - I assume it's the Opfor, so I unload several dozen rounds through the door - killing my hapless teammate - who'd also thought to check the building. I then wander through the door - feeling somewhat stupid, and am promptly shot by my remaining teammate - who gets kicked out of the game. From a 3 on 1 situation, to a total loss.

I was wondering if anyone else had done something quite so silly.