Once a player becomes unconscious, his/her body will begin o slide across the map and through walls, making it impossible to revive them, bandage them, loot them, or finish them off. It has happened to me several times, and has also happened to someone that I hit with a crowbar. The problem is that the only solution is to log off and back in, and now if you are unconscious, you die for that, meaning that there is no way to help someone back from unconsciousness or to be helped.