With all maxed it is possible to bea the boss easy. Let the team handle the zombie crew, you only need focus your ammo in the boss and the semi perma stun works fine. I only need use a tactical nuke once and the time stop twice. No life loss, no move from the boss and no one zombie reach the shelter. Remember, focus your firepower in the boss y let the rest to the team. All maxed.
 "Zombo Buster Rising"){kind=icon}
 "The Enchanted Cave"){kind=icon}
 "Flight"){kind=icon}