The egg cooker is a mystery to me. What is the hole for? I hard-boil eggs by heating a pot of water containing the eggs. Why would you puncture the shell?
I do not know about TFA and the egg cooker, but I usually boil the water first so I can pull the eggs out at a specific time (6:30 to 7:00) so the yolk is gooey. When I put an egg into boiling water without putting a hole through to the air sac, I think there's a higher chance that the egg will crack and spew albumen throughout the boiling water.