Well, one of my staple short-cut breakfasts consists mainly of two eggs in a coffee cup, having been previously sprayed with cooking spray ... a little salt & pepper, and stick 'em in the microwave for a couple or few minutes on medium-low and you get something like poached eggs. I did, however, occasionally have problems with them exploding due to steam buildup inside the eggs, and I started stirring them first after that. That seemed to break up any serious vapor barriers, at least at lower power.
But then you get something more like a cross between scrambled and poached, and this morning, I decided I wanted something more like poached again.
So I didn't stir. Put them in for 4:00 on 30% power... and they weren't quite done. Sometimes when this happens I just turn it on 100% for a few more seconds to finish it off.
I decided to do that this morning. Only I punched in 30 seconds. I had something to do on the deck for a few seconds so I went out there.
Excactly 29 seconds into the cook time, I hear this loud FOOM! and the clatter of the coffee cup on the glass turntable. Usually that amounts to a little spatter but mostly everything's still intact. But this was louder than usual.
I went back inside, and saw that the explosion had blown the microwave door open! There were a couple tiny bits of egg left in the cup. So I figured that steam had pushed the egg up to (and maybe out of) the top of the cup so the egg was not constrained anymore by the cup and it was all explosion.
After I regained my composure from laughing and a little disbelief.... I took this picture.
Egg coated every interior surface of the microwave.
Yes, sweetie, I did clean it up. :-)