After getting out of the crystal cave on XEN (chapter 5), I have to jump over some floating platforms, until I arrive to the very first such sticky grenade launcher which is out of ammunition. Across the gap there is a tall tower, and two Vortigaunts under the tower. As soon as I get close, the tower starts to "power up", and it makes connection lines to the two Vortigaunts which will then be presumably mind-controlled and attack me, but then the game crashes silently.

This happens always upon reloading. The game runs smoothly even on max graphics settings, but crashes here even on the lowest graphics settings.

If I quickly snipe the two Vortigaunts before the tower starts to do anything to them, then I can proceed, so it seems the crash is connected to the event of the tower connecting itself to the Vortigaunts, or them attacking me (but back on Earth the Vortigaunts could attack me without any problems)

The game still becomes unplayable, because I have to enter the small container outpost, and then new Vortigaunts appear, and I cannot stop the tower from connecting to them as they appear while I'm inside the outpost. And then it crashes again.