It's because the game thinks you are moving at a huge speed while actually you are stuck. This can occur in some maps (transit, sokolov) in places where you can get stuck falling, and then suddenly die cuz of gravity. And if you use timescale 0.1 while watching demo, you can see the flames flying out of where the player is and then after hitting a surface, stopping and for some reason turning around. The spinning is caused by your player model being tilted/rotated slightly when you move, but in this case it is rotated A LOT, and if you change your viewing angle, the model has to rotate a lot to get to the new position. So it is probably just 1 same bug. If you move fast enough, you can get out, that's why you die in those places in those maps after some time.
