My camera is (was) on a retractor with a squeeze clip. My magnetic slate is also on a squeeze clip on the same side, but a slightly different shape. This is what I think happend. I went to unclip my slate and squeezed the camera retractor clip instead. Relaizing the error by feel, I stopped squeezing and moved to the slate clip. The retractor was pulling on its clip the whole time so even though I did not fully release the retractor clip it was probably not fully engaged and at a later time it pulled free. With the current rocketing me along, that camera bouncing around anyway it released and I didn't notice until the safety stop.
Lots of ways I could have avoided this. First, if I had used a C-clip for the camera this couldn't have happend. Second, I should have stuck closer to my buddy and she probably would have seen it. Third, .... well, you get the point.
P.S. Pictures (from the first dive)are in my gallery. At this piont I would be happy if I got the card back, if not the camera.