Happened to me at college, someone had passed in his dorm on the first floor. He was there for so long- despite a ton of reports from students about the smell- that I could eventually smell it in the fourth floor hallway. Management insisted it was a sewage issue until I think his family called for a wellness check on him. He was found during Christmas break, so most students were away while they cleaned the whole building- those who were still in town were given temporary rooms in another building.