Signs of the Infected

You walk backwards towards the door. You know you have to leave. You know this psycho killed this woman and is going to do the same to you if you stay any longer. He laughs maniacally as he follows you out of the living room. You don't turn your back on him. You reach for the shotgun behind you. The man keeps coming towards you. He is going to kill you.

You fire the gun without a second thought.