On day, one of the helmet crabs stop moving. She was still by the food bowl kind of hiding herself for 2 days and not moving. So I took her and put her to the very shallow water about 30 seconds , she did not move. When I took out of the water, she kind of fall off from the shelf half way. I just placed on the sand gently.

I am sooooo sad!
Was she dead or was she malting but I moved her?
The sand is about 2 inches(not deep), that how school keep them.

I don't know what to do. If she was molting, I like to save her. What should I do?! Please help her!!!