No, never microwave a whole egg in its shell. Steam builds up faster than the shell can vent it, and the egg can burst violently, even after it's out of the microwave.
Boiling eggs on the stove takes time, so it's a natural instinct to look for a microwave shortcut. The problem is that an eggshell isn't built to release steam the way a pot lid or vent hole is.
This isn't a texture issue, it's a genuine burn hazard, which is why it's worth understanding exactly what happens inside the shell.
A microwave heats the moisture inside the egg unevenly and fast. That moisture turns to steam, and pressure builds inside the sealed shell with nowhere to go. The egg can rupture inside the microwave, spraying hot egg across the interior, or it can appear fine and then burst later when pierced or bitten.
This is the part people miss: an egg that looks intact right after microwaving can still be under pressure. Biting into a microwaved hard-boiled egg, or even one reheated after boiling, has caused burns because it can burst in the mouth.
Even a peeled, already-cooked hard-boiled egg can build pressure in the microwave. If you must reheat one, slice it first so steam has somewhere to go, and heat in short bursts.
Keep whole eggs, shell on, completely out of the microwave, no exceptions. If you want a microwave method, crack the egg into a vented dish first and pierce the yolk before heating.
It's risky even peeled, since trapped pockets of steam can still form. If you reheat one, slice it in half first and heat in short 10-15 second bursts.
Yes, scrambled or beaten eggs are fine in the microwave since there's no shell to trap steam. Stir every 20-30 seconds and stop once they're just set.
Steam pressure can stay trapped inside the shell even after heating stops. The egg cools slowly, and the pressure can release suddenly when it's cracked, poked, or bitten.
Yes, cracking an egg into a microwave-safe bowl of water and piercing the yolk before heating in short bursts is a common, safer method than boiling it whole.