I figured out that the DC doesn't come from killing mobs on a higher level *map*, it comes from simply killing higher level mobs on any map. I took Demon Syth and moved him onto the lower level part of requies, and it still DC'd my character.
So, does anybody know how to find this part using CE or olly? It would have to be a call or cmp, followed by a jnz or je which jumps to the DC...but I'm not sure how to find this, since the game will DC and close every time I try to make a BP
Any ideas?