Well these are the two methods of it working:
Zombie within X or barrier Y, wait Z, coloff, alphafade = 0, (rebuild: person pressing A, colon, alphafade = 100)
Zombie within X or barrier Y, wait Z, coloff, alphafade = 0, (rebuild: destroy, barrier set to infinate spawn so the physics are re-written.)
Knxrb is the one who is writing this and apparently the problem is turning collision on. The dark physics needs to be re-written of sommin. He will be able to answer in more detail any questions. I'll see if he's on msn now.