Why cant snapping turles eggs hatch if they arein the water for more than an hour?

In a reptile egg there is a 'tube' that develops soon after the after the egg is laid, this allows the embryo to get oxygen through the egg skin, so if the egg falls into water, the oxygen supply stops and the embryo suffocates, same as if the egg is disturbed to much the embryo will be killed by the oxygen sack being drowned....