Once in the Laboratories, enter the second room to the left where you will find the Power Switch inside. Turning on the power will allow you to access all of the different teleporters around the map, giving you the freedom to travel to all three different floors of the Pentagon.

'Classified' is available as a standalone purchase, or as part of the Black Ops Pass*, which includes four additional Zombies Experiences for Call of Duty: Black Ops 4.