This bug relies on two scripts. One script teleports you back in a zone as soon as you leave it, and the other script spawns an explosion relative to you with a strength of 0 and radius of 1 on a loop while killing you at the same time.
Script 1 (Set as the leave script for whatever zone you are in)
Teleport [player] [x,y,z inside zone]
Script 2 (The one you manually run when you want to leave the map)
1. Health [-100]
2. Explosion [prel:0,0,0]  
4. Loop 
Once outside of the map there will be constant explosions at lower y values of (0,x,0).
If you fly above them you won't die. The script will continue even when canceled. Any attempt to leave (0,x,0) will not work unless the map is reloaded (It can be saved or not).