Congrats on the win.
The mustard gas exploit isn't exactly new, but since I haven't played the newer development builds I didn't know (or forgot) they specifically made changes to make throwing gas grenades turn Attnam hostile.
I personally wrote out a guide on exploiting mustard gas grenades for IVAN CVS and LIVAN
six years ago. It's also on the wiki. That's probably why they changed it, heh.
I really like the fact you've found a new and much more interesting method to work around the changes to gas Petrus though, that's super neat and, as a result, might get patched out now