Instructions
Load "Call of Duty: Black Ops" on your console and select the "Yes, Update Now" option when prompted to update the game. The most recent updates will now be downloaded and installed to the game. If you aren't prompted by such a message, the game has already been updated.
Select "Five" from the "Zombies" section of "Call of Duty: Black Ops" and then go through the door and into the elevator. Kill zombies as necessary when you encounter them.
Get off the elevator and play the game as you normally would. Continue opening doors and entering new areas until you find the power switch. Press the button indicated on screen to activate it when you find it and then go back to the main room. In the main room will be a red machine. Walk up to it and purchase "Juggernaut" when prompted.
Walk up to the teleporter in the center of the room and play normally until you see a zombie crawler. You will use this crawler to get on top of the teleporter.
Jump onto the barrier behind the mystery box and turn to face the crawler. When he gets close enough he will hit you. As he hits you, jump and press the left-stick back to get on top of the rail behind you.
Run towards the rail next to the teleporter and jump right at the edge before you fall. You will land on the next rail; walk straight forward to get on top of the teleporter. You can stay here as long as you want and the zombies won't be able to get at you.