When on No Mercy's Gas Station level have a player pull the switch to lure in the horde. Eventually a tank will appear in the fighting. If the survivors are desperate they can send out a survivor to distract the tank. The survivor will then run to the Gas Station with the tank following him (hopefully). After that have him or another survivor blow up the Gas Station. The tank will be dead but so will the player that lured him there. This is a good way to have low-health survivors heal in this area.