I do believe the fight was about CR being with Lauren, JMO. But they were her BF's friends, possibly not really hers and therefore may not have been in any position to try to convince her to stay with them. Also, perhaps CR said something to "invite" a punch, in their minds. MYOB, or something along those lines. Tempers, and fists, fly under the influence.
This is kinda OT, but back in "my day" lol, one could still drink at 18 so we drank as a matter of course in college and it did not seem to be such a big deal. I never heard of anyone getting alcohol poisoining during my entire time, and seldom saw people passed out or shoeless, etc...and as it was a state school, no one seemed to have money for anything more than weed. Sometimes I think people tend to drink more when they are doing it illegally than they might otherwise...JMO. (Also, I find it beyond ridiculous that people who can vote, etc. can't buy a beer, but that is another story.)
Not to say people did not get "wasted" but it never seemed to reach epic proportions. I know there are far more "designer" drugs out there nowadays and much else has changed as well. I see some of these kids with over 2000 "friends" on FB, and wonder if I have even encountered that many people in my 40+ years...