Bloody Metro

Another crazy tale of the Paris metro:
So I'm leaving the Musee d'Orsay with a bunch of people from my program (we went on a tour and it was great! they're very strict there--the tour guide made my friend and me spit out our gum and she went up to this random man and told him to get off his cell phone....) and I'm walking with my friend, Andre.  I hear this noise behind us and I turn to look, and there's this group of 4 older teens, maybe 19 or 20 year olds, talking really loudly and goofing off. But my attention is drawn to one of them in particular on account of his bloody right hand. It's got a white gauze bandage on it, but the blood is seeping through. I say, "Andre, check it out, this guy has major carnage going on," and when we both turn around to look, I swear to God, his hand has gotten bloodier.  So we get on the moving sidewalk in the metro, and the group of kids starts to pass us. The guy with the bloody hand is last, and I'm pressing myself up against the right side of the moving sidewalk to avoid contact with his possibly diseased and almost certainly drugged blood. Once they've passed, I look down, and there is a path of little blood drops along the moving sidewalk! Ew.
Also, he had blood all over his belt and underwear from where he'd been pulling his pants up using his bloody hand. I'm thinking, wow, this poor kid is really hurt, but the next thing I know, he's jumping onto the middle part that's between the moving sidewalks and he's running down it to get to the front of his group of friends. It is at this moment that I lose any and all sympathy for him. He's obviously very reckless and is in no pain on account of all the drugs he's probably on. I then proceed to follow his dribbled path of blood (which is growing more pronounced by the second) to the platform where we're waiting for the same train. I made a point of not getting on the same car as him (obvi), but when I got off at my stop, I walked by the car he was in, and before the doors closed, I saw him sitting in one of the seats by the door with this pool of blood at his feet.
Oh yeah, and he was smiling and laughing with his friends like nothing was wrong.
WHAT?!?!
I asked the French guys sitting next to us at dinner that night if that was in any way normal (because absolutely no one in the metro station seemed overtly alarmed by any of this), and they said no. However, they did say that it was normal for Parisians to say nothing to him about it in case it might "vex" him.
French people are odd.

Mais, que sera, seara.