I poach an egg in the microwave nearly every morning. My method is: pour a small amount (approx 1/8 cup) of apple cider vinegar into a coffee cup, add generous 1/2 cup of water, mix well, crack an egg into the cup (smaller cup with semi-rounded bottom-no sharp corners), microwave for 60 seconds at 70% power. Eggs are variable so sometimes i have to add or subtract a bit of cooking time*.
*Note: I use JUMBO nest fresh eggs. Smaller or less fresh eggs require adjustments. You have to tinker a bit to get it right. In a weeks time I will still have a egg or two that won't be perfect.