Unfortunately, it is illegal to have a gun at most schools. And really, the friend couldn't find a better time to return the rifle? I'm a student and I would never leave a gun on campus or bring one onto campus. It's illegal, stupid, jeopardizes my future and everything I have done, and the risks are just too high for the reward. The slim probability that I will need a gun to defend myself or stop a shooting at school is so much lower than the probability that I will get busted. 9 pound, 34 inch long stamped steel secrets are very hard to keep even if you can control access to where the secret is held. Things go missing from dorm rooms all the time. Throw in alcohol, drugs, lack of sleep, girlfriends, parties, visitors, group work projects, misplacing keys, and lack of respect for privacy, and unless you are a recluse in a single, the difficulty of keeping the secret rises from insane to insurmountable.
The bitter problem is that the schools maintain that we are the safest when we are the most defenseless and the only people who make media attention for their guns at school are school shooters. Therefore, gun=insane=violent=massacre. And other weapons are not allowed either, and don't trust campus security to believe in probable cause or side with you on an issue involving weapons, contraband, or even talking about such things. Even a totally passive thing such as concealable Level II or IIA body armor is going to look really out of place and why would you have body armor unless you were planning to go up against guns? And who has the guns? The Police. Personal defense and safety are really a crapshoot for college students. IF you live in an off-campus apartment not controlled by the school, then you can get away with at least being able to defend yourself there.
No disrespect to Campus Security, but being unarmed, having no arrest power, and not having any sort of body armor doesn't go a long way to building confidence.