A glass storm
Have you ever been in the wrong place at the wrong time? Or, even worse, the right place at the wrong time? If you haven’t, you should realize just how lucky you are. Leaving ten seconds too early or ten seconds too late can mean the difference between being showered in glass and getting safely to school.
While preparing to leave, the OP decided to take out the trash, which delayed his exit from his apartment by ten seconds. While he was walking out, some moron on the third story tried to toss a bag of glass into the garbage bin, which only ended up shattering in front of the OP.