Subway (1985) - Anyone else OBSESSED with the sound design?

Okay, so I just rewatched "Subway" (1985) the other night and WOW. I know it's Luc Besson, so visuals are like, baseline good, but I feel like the SOUND in this movie is criminally underrated. Especially considering the whole setting is, well, a subway. Specifically, I was geeking out over the layering of sounds during the chase scenes. When Fred's being chased by the businessman's goons, it's not just generic "running through a tunnel" sounds. You've got the echo of footsteps, the squeal of train wheels in the distance (sometimes close, sometimes far!), the actual subway ambience, and then all this 80s synth layered on top. It creates this crazy, claustrophobic, almost surreal feeling that really puts you in Fred's head. Did anyone else notice how they play with perspective and distance? It's like they're using audio to tell the story as much as the visuals are. And speaking of the music, Godard's score is so perfect for the feel of the film isn't it? It's so synthy and '80s that it's campy, but it works so well with the film's visuals. I wonder, has anyone looked into the technical specifics about how all this was recorded. It's so difficult to get usable recordings like this in a real environment with trains.