I was playing and everything was fine, no crazy FPS fluctuation, haven't got out the first lab and was about to pass the point when the tutorial tells you how to crouch when my PC completely shut down. Now, obviously, my PC ain't worth 10k, but let me assure you it can easily play games like Red Dead Redemption 2 without any stutter, Grounded 1 at max settings as well, Spider-Man Remastered, Xcom 2 with 800 mods, and so on. I'm just making this disclaimer so to not prematurely jump to conclusion that it is a PC problem and not an optimization one. Hope this report is of some use.