Aaaaand here we have a "I cant leave it alone now that I've seen it happen" type of MC. Now MC is gonna get in trouble for sticking his neck where he shouldn't and also that will make the girl fall for him causing the drama we all know is going to happen.
If MC had brain and a working phone cuz in this stories the phones never have battery or working cameras, he would have filmed a video of the bullies extorting the girl and shown it to the teachers in an anonymous way and have all of it solved already (if the teachers actually do something cuz in this type of stories the teachers are usually useless, are part of the extorting, or one of the bad guys has some power over the school and so they let them do whatever they want). And in that way MC would have saved himself from lots of plots and dramas.