I am not blaming the victims, but surely they knew better than anyone what a complete lunatic Elliot Rodger was. Self-preservation might not be PC in some circles, but it’s actually the right thing to do. When someone is obviously not right and getting worse, report to parents and police. If that doesn’t work, run away, move out, gang up.
I wouldn’t allow a kid of mine to even bunk away at school. I was a day student travelling into NYC every day - exhausting - but it kept me away from the drug culture that was going on in the dorms at the time. All my friends were middle-class kids; not spoiled, bored rich kids.