I've been experimenting with the linedef deletion using some maps with a pain elemental and can see it has to do with the lost soul exiting the map from the top or right out of view. Here I have it done on Hangar, Threshold of Pain, failed on Command Center (as it was leaving the map from the bottom and left) and Military Base, ending with the cache miss on lump 0 error handle at the end of the vod. I am testing this out on a phat ps2 and original longbox copy of the game. 9:30 for the first clip -