Did it three times out of 5 attempts. Game crashes to desktop without memory overflow nor excess CPU load. To reproduce:
- go Deep Caverns, be friends with Faceless, pass Faceless commander's mind reading on good terms;
- go Thortists' outpost, complete their 1st quest (scouting Faceless base), take the 2nd (free captive Rassophores);
- go back to Faceless' base and pickpocket the key to Rassophones' holding cell;
- go outside, enter stealth, open holding cell door without getting detected;
- go outside again, then stand where i do on the screenshot, manually start combat when no faceless is in LoS and cast Pyrokinesis, aiming it as shown on the attached screenshot, then end combat;
- now while everyone is going to Pyrokinesis' impact point, walk into the prison (no need for stealth), close the door once nobody's inside and quickly talk with a rassophore, take 2nd option;
- stand inside the prison doing nothing.
And then the game often crashes few seconds later - during real-time combat between Faceless and escaping rassophores. And if it doesn't crash, then there's visible hickups and lag during this real-time NPC combat - animations frequently pause for several frames. Probably depends on exact landing spot of Pyrokinesis and how exactly rassophores move outta their cell (sometimes one or two got semi-stuck inside, sometimes not).