Load the map offline. On clipboard, go to Options->Arena Setup->Environment->Arena Settings. Scroll down til you see Ground Auto Lethality[Armored]. Highlight it and hit the Change button. Change the setting to .0001. Puffy ack will no longer hurt you, it will be just for immersion effect. Turn down the Ground Auto Lethality[Hard] also to not take damage from auto ack if you want to do so. Then start the mission. <S>