Power/Pack-a-punch - Make your way to the teleporter as quick as possible which you can get to buy opening the door next to quick revive. Now you need to charge three aether reactors which you can get to by opening any of the doors and then following the game hints. You will need to protect the reactors from zombies and once its done you should no longer see the meters on the side of your screen. Now if you teleport back to spawn and go to Ravenov and pack-a-punch will now be avaliable.