You must have 2 or more players for this to work.

On Verruckt go into the room where the denist chair is and in the small doorway the host kills themself.

Then the other people finish the round, and when the guy who died respawns he goes into the back right of the room by the dark corner.

Then the other guy goes on the other side of the back, on the left and all the zombies horde up where the host died.