My hermit crab lost in its crabitat...?

I have 2 hermit , 1 of which is sitting right here, and the other one is..somewhere in the aquarium cage. I have a 20 gallon terrarium and I use that coconut fiber stuff that looks like dirt. I have at least 2 inches of it in there and the hermit crab buried itself deep somewhere. I can't see it anywhere, and I am scared to rummage my hand through there, what if its molting? If I touch it I might mess things up. My hermit crab next to me- what do I do? Do I put it back in the terrarium? What if it hurts the maybe molting crab? I have only had these for 4 days and they switched into the spare shells on the first night- if thats any good info- please help ASAP!!!