Okay checking the debug log in my Fallout 2 folder location here's what I found when fighting in New Reno>Second Street
computing attack...
sequencing attack...
Loading sound file HMMETLAQ.ACM...tyring HMXXXXAQ.ACM succeeded (with alias).
Loading sound file NMBRLPAN.ACM...tyring HMXXXXAN.ACM succeeded (with alias).
Townsperson is using Coward packet with a 25% chance to taunt
Townsperson said message 2073
running attack...
Loading sound file ib2p1xx1.ACM...succeeded.
Loading sound file ib2lu1x1.ACM...succeeded.
gl_p_party_orders: set burst mode to 0 for Cassidy
gl_p_party_orders: set burst mode to 0 for Sulik
gl_p_party_orders: set burst mode to 0 for Vic
Loading sound file icombat1.ACM...succeeded.
Prostitute minHp = 18; curHp = 45
>>>NOTE: Prostitute had extra AP's to use!<<<
>>>NOTE: Casino Patron had extra AP's to use!<<<
Prostitute minHp = 18; curHp = 45
>>>NOTE: Prostitute had extra AP's to use!<<<
Prostitute minHp = 18; curHp = 45
>>>NOTE: Prostitute had extra AP's to use!<<<
Vic minHp = 41; curHp = 40Vic is using PARTY VIC CUSTOM packet with a 25% chance to taunt
Cassidy minHp = 26; curHp = 100
ai_danger_source: I couldn't get at my target! Picking alternate!
Sulik minHp = 31; curHp = 111
ai_danger_source: I couldn't get at my target! Picking alternate!
Casino Bouncer minHp = 22; curHp = 85
>>>NOTE: Casino Bouncer had extra AP's to use!<<<Townsperson: FLEEING: I'm Hurt!Townsperson is using Coward packet with a 25% chance to taunt
zicrtrnk: trunk: map_update_p_proc
zicrtrnk: Trunk_In_Party: start
zicrtrnk: GVAR_CAR_PLACED_TILE == 22500
zicrtrnk: trying to hide trunk
zicrtrnk: Trunk_In_Party: end
Prostitute minHp = 18; curHp = 45
Notice how the last line says "Prostitute minHp = 18; curHp = 45" Before the game crashes a prostitute animation play on one of them as if they're "using something". (You know the Player Character animation when he uses his skilldex.)
I noticed this, a prostitute in the vicinity frequently uses what I believe to be the chem "Jet". Which causes the crash.
More Specifically
What happens in combat is, a random prostitute that I'm not engaging in combat with uses Jet. And the game crashes as soon as that happens. I only know it's Jet because when the crash first started happening I caught the game message displaying on the pip boy message screen saying "Prostitute uses Jet". Also in Virgin Street, New Reno I have fought random NPCs in the Desperado Casino before, and the prostitutes outside would use Jet for some reason. With no crashes to the game.
EDIT: Problem solved as posted in this thread
https://www.nma-fallout.com/threads/fo2-engine-tweaks-sfall.178390/page-164#post-4460707