Maybe the Mallers just rolled on up and walked in the front door. If the Colony knew they (Colony) were ass out on weapons and ammo and a sizeable group of well armed SOB's rolled up to the front door and said open it or we are going to kick in your door and let in the zombies, they might have just opened the door and submitted to the supieor force. Happened a lot throughout history, and faced with death or life, well the choice is obvious.