Never put a poptart in a microwave for more than 20 seconds

I brought a pack of smores poptarts for a snack on my break at work yesterday. They don't have toasters in the break room, so the next best thing was the microwave. I'm in hot pocket mode. I punch in 1 minute and let it cook. The one minute is up and I smell the most terrible burning odor ever. I look at the microwave and smoke is coming from the edges of the door. I open the microwave door and an explosion of burning poptart smoke shoots out. I immediately shut the door and try to fan out the smoke so it doesn't cause an alarm to go off. I write a note that says I burned a poptart in the microwave and don't open the door if it is still smoking. The whole breakroom smells like burning funk. Someone told me poptarts are only supposed to be microwaved no more than 20 seconds. How am I supposed to know that? I always toast them.