It almost happened once with a classroom of kids. True story, a teacher was getting upset at the kids in his classroom acting up, he soon had a heart attack at the desk and slipped to the ground. The kids didn’t know what To do and sat there in silence for awhile until one kid said that somebody needed to do something and then one kid got up and alerted the principle who call the ambulance. They later said that teacher was almost gone
I'm guessing this was the day he taught the difference between "principle" and "principal."