I was on a liveaboard in Turks and Caicos, where, depending on how the boat was swinging on the mooring, you might have been doing a giant stride into 4000' or so of water. At one point we swam away from the wall and into the blue--a little disorienting. I thought I was level in the water until I looked at the angle of my compass in the housing.
The round the world swim to Egypt would have sucked too

Wrong blue hole Ron.
Done it deep a bunch a times. Very easy technical dive.