thoughts on the bridge scene?

Genuinely one of the most confusing scenes from any movie I've ever seen in retrospect. Not because it's actually more confusing than some scenes from other psychological horror movies but because you don't expect anything like this in this movie, and certainly after having finished it, it feels very out of place. This isn't a movie that's supposed to leave you thinking like The Shining.

It's just a pretty by the numbers horror movie, so wtf was with the guy at the end of the bridge that made the guy drive off with the girl? I cannot wrap my fucking head around it. It's the only scene in the entire movie that someone else other than the black guy reacts to something abnormal. And not only is it not the girl that notices and flees, BUT IT'S THE GUY THAT TURNS OUT TO BE THE MAIN ANTAGONIST. The main antagonist, the guy that kills the girl in the end, and is seemingly the heir to the vampire throne or whatever, is scared of a guy at the end of a bridge that slowly walks towards their car.

WTF? As I said, this isn't The Shining where you have the guy in a bear costume giving someone a blowjob and even though it doesn't make sense, it fits within that movie as it's just that kinda movie. But Spiral (2020) is not that kinda movie, SO WTF IS GOING ON? I swear to you, I've seldom been this confused by anything in any more ever, and I need an explanation.