Someone on another board mentioned "bleeding in the stomach." It does make perfect sense. Men do not come straight forward, rushing out of the bathroom screaming, " I'm pooping blood." We tend to try to hide the fact, and hope it will "just go away" on it's own. If he kept waiting he might have finally passed out. ( Something else that was mentioned earlier.) If so it would be the perfect time for a roommate, teammate, coach, etc. to say, " Dude, your going to the hospital!" Also, if he waited too long his labs would have been bad enough for the Dr. to decide to give him blood instead of regular IV fluids. Blood, would mean an automatic hospital stay, but maybe not a trip to the unit.
I am certainly not saying 100 % this is what happened, just saying that it fits using the scientific method.