So me and my two friends have had this idea, when we play versus just the three of us, when we got tank we would kill the AI, then follow our friend(the last survivor) to the saferoom. and have to protect them, from getting killed by the AI Special Infected. So were hoping this could be made into a mutation.

-Infinite health tank

-No anger meter, so no AI tank

-Must defend the last survivor, and escort them to the saferoom