She didn't boil them, because she needed too much gas with an extra pot on the stove.
In her time that meant the gas would stop, she had to turn out all the burners. Then she had to go downstairs, put a quarter in the machine, go upstairs again and light all the burners again.
It was not very beneficial for the food to stop the heat halfway.
So she took the eggs and put them on top of the potatoes.
When the water boiled she watched the clock and gave them about 12 minutes.
Then she caught them with a large spoon and put them under cold streaming water.
When my uncles would open the lid she would get angry, because the eggs needed a bit more time extra.
I don't think she did mind that, but she didn't want my uncles to be so curious. LOL!