Ed Teixeira of Two Hour Wargames was one of the convention guests of honor. He ran several games of All Things Zombie. The mission, each time, was for the players' characters to rescue the innocent from the zombie horde. After cooperating (mostly) to get the rescued out of the village, the players invariably (by coincidence or design) wound up shooting each other in order to be the one to get the innocent off the table (and thus achieve the victory). The interparty bloodshed did have the result of distracting the zombies from chasing the rescuers – instead taking advantage of the buffet of slowly cooling corpses.
The successful player in the first game was one whose character had broken a leg falling off a cliff - thus missing most of the "friendly" fire - and was able to complete the rescue by escorting the innocent away from the corpse of her previous savior after shooting the party member that had blown that unfortunate away.