This glitch will keep the zombies away from you. To do this, you need at least 3 people.

First, all players go to the room with the window and Quick Revive machine. 2 players drop down into the hole, and they both go in the opposite corners as deep as they can go.

The 3rd player stands up at about a certain spot up above right on the brown boards, but it must be exact.

If done correctly, zombies should only attack the 3rd player from the window, and the rest of the zombies go back in forth where the STG-44 is.