If you see the gun mystery boxes around the various locations (usually 1 per room) you will see a map above them. When the power is turned on, the map will highlight in green which room the box is. The pack-a-punch machine is in the middle room (Theatre) and you need to use the teleport to get to it. You need to link the teleport with the link thingy in the 1st room (looks like a circle in the middle of the room). Zombies rule!!!