So this guy had an accident and there was something coming out of his nose!?

I know this is kinda gross, but I'm really interested. Last Sunday my friends and I came back from church and we saw this old man fall of his bike hitting his face on the concrete. We rushed to help him back up, but his nose was bleeding so hard it made him dizzy. There was also some white stuff coming out of his nose that looked like pus, but I'm sure it wasn't. What could it have been? I wanna go to med school so that's why I'm interested in that kinda stuff.. ;) thx!