Buy a plastic suction dart gun prior to the rampage. Make it look real, as in modify the plastic to such an extent to possible even increasing launch speed. Possible by making an air tank.Wen ready, fill gun with darts. Grab some broz, have them put blue makeup on so that they look like zombies. You dress up as a badass. Go into walmart, chose your station. Preferably the toys section so if you run out of darts you can refill. The zombies will have the entire store to hide and attack you with. When ready, run out of the station and shoot all your zombie broz.When the manager talks to you, point the gun to his head and ask for all his cash.By then the police should be there.