When I was a kid my father was watching a movie that I think was recorded into VHS, it looked 70s to 80s, the location had some trailers like the ones construction sites have, there was this blonde guy who seemed nice at first and was talking to a lady, I walked away but when I came back sometime later into the movie the blonde guy went psychopathic and was chasing the lady up the trailer stairs and I remember one shot of the camera pointing directly down at him running up the stairs blood on his white t-shirt with one of his eyes twitching like he’d gone berserk or was hit on the head. The way I imagined it was that the guy went insane or was pretending to be nice but was a sociopath or psychopath.