There are good ways to react when being fired and then there are bad ways. Stripping down naked is never a good reaction to being let go. Doing so when you're a teacher at an elementary school is probably much worse.
Luckily the teacher got naked after the kids went home, though I'm sure all the kids already know about it. Of course, stripping is at least a non violent way to react when we keep hearing about shootings and such.
File that under sex ed.