In most cases of first trimester Vanishing Twin Syndrome, there is no physical impact on the surviving twin. A healthy womb experience followed by a normal delivery should be expected. A late pregnancy occurrence of VTS does have some implications for the surviving fetus, just as for the mother.
Depending on how cooked you like your hard boiled eggs, the eggs should be done perfectly in 10-12 minutes. That said, depending on your altitude, the shape of the pan, the size of the eggs, the ratio of water to eggs, it can take a few minutes more.
My mom gave me very similar directions on the perfect hard boiled egg recipe. Except she said from 11-14 minutes on the egg...maybe it depends on the size of the egg or the freshness of it. But we usually averaged it out to 12 minutes.