[quote=Vordak]
::: Swim towards the surface and turn around, holding the crab up to help Mtn aim.
[/quote]

Change command to:

::: Grab the crab's pincer, pull it over to a solid surface, making sure that it wont sink into the sand, and then step on it's head, pinning down the little pest. Pull with all my might, tearing the crab's arm off, and if succesfull, keep crushing the fiend underfoot while also trying to cave it's face in with the torn off pincer.