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.
This is where your timing needs to be precise. If the eggs sit in the hot water too long, they will overcook and end up with a green yolk. Extra large eggs will need 18 minutes to fully cook, large eggs need 15 minutes, and medium eggs need 12 minutes. Set a timer to prevent over or under cooking. For soft-boiled eggs (runny yolks, solid whites), let the eggs sit for 5 minutes less than the time needed to hard...MORE cook the egg.