Wow..I wouldn't care what the reason was either. No excuse. Even if the "hospital" excuse is true - it could've been handled differently. He could've called you while you were in the bathroom. He could've walked towards the ladies room, banged on the door if it was a one person bathroom.... found someone going into the bathroom to tell you he was there and needed to talk to you... etc.
You don't just get up and leave unless by some unlikely coincidence he was looking out the window and saw his friend have an accident.