I wonder if it was the salt that made the difference as I've never tried it myself, but found this video that claims it works to boil eggs in a microwave and all she did was add 1/2 tablespoon to the eggs covered with water.I tried three different times.....
First try, I just put the egg in by itself. Three seconds later, it exploded.
Second try, I covered it with water. Five seconds later, it exploded.
Third try, I poked little holes in each end and covered it with water. Five seconds later, it exploded.
My house smelled for a week!