Swallowing semen from different partners at the same time?

My college roommate with her "guy friends" had a sex party... after she performed oral to all of them, yes she swallowed, and after 2-3 hours she had horrible stomach/intestinal pains. It was not like wanting to throw up but from a slight body movement her stomach/intestinal would give her this disgusting heavy pain. So I was wondering if this may of been from swallowing the semen from different male partners at the same time? No the guys were physically healthy as far as I know!