Missing mithrax crab

Hi i have a question that someone might be able to help with

i last saw my green mithax crab about 2 days ago (it around an inch) after i lifted a rock and saw it dangling under it i havent seen it since and there no sign of it. no shells/body no smells to indicate dead thing etc

Any ideas if there a good way to lure crabs out hiding im trying a raw shrimp piece tonight incase its food needed

I just also tryed flipping every rock other then the big skeliton one it hides in normally (i think it tonga shape as looks like ) and no signs still even putting lights deep into it hidden not even a leg that i can see

Id like to see it out more as while its hidden there seems to have been a brown diatom outbreak or something as the live rocks turning brown/orange on parts while coraline spread on others is exploding

The big rock also seems to be growing what looks like roots which im not sure what they are (possible worms?)


Overall question is is my crab still alive and just hidden or something and is there a way to tell if it died and do these things bury in sand (only other option i can think of)