1. Go open any door in Der Riese from the mainframe.

2. Go to the telepoter near the cat walk.

3. Go in the hole where the grenades are.

4. Stand/crouch in the right/left corner of the bottom corners.

5. A teammate will need to go where the revive machine is and stand in the wall corner above the whole two walls, back from the window.

6. Your zombies will appear in the teleporter room where the cat walk is.