One Time At School

Back in high school, about 4-5 years ago, an ambulance was passing outside our school complex (we were on the third floor). I got off my chair and went to the window, without realizing it was closed (we were in late spring, so they were open most of the time). I crashed my head on it. My glasses fell off my face, and the class stood in awkward silence for about 3 secs before exploding in a massive laugh, teacher included.