Its not v21. here is what i do:
first, put a zombie spawn. name it "zombielol" or something.
go to make a minigame and disable director.
i never understood director and it has a weird way of spawning zombies and often doesnt at all.
make the mini, and wrentch a spawn to be a zombie normal. the zombie will spawn in your face and kill you and work fine.
now, when you kill a zombie, the spawn is still set to zombie normal, so it will respawn instantly. this is really annoying for me. so get your wrentch and use bot events like so:
onbotkilled>self>setvehicle>none.
now when u kill the zombie it wont respawn.
make a brick and event it
onactivate>namedbrick/zombielol>setvehicle>zombie normal
to respawn the zombie without it going in your face.
i use ontouch events with invisible bricks on my zombie hotel.
this is a horribly disorganized cinderblock of text so i'll answer any questions you have for awhile.