keep hearing pistol shrimp..

So I have had a pistol for a few months. I added a tribal blenny that decided to move into the rock he is under. All was quite until I added my pink spotted watchman two days ago. The watchman moved in with pistol after maybe 2 hours of being in the tank. I can see them under the rock but they haven't came out yet. The blenny has been sleeping in a hole that's in the same rock. I'm thinking the pistol maybe decided he wants to kick the blenny out now??? Seems like I only hear the noise when the blenny is back in the hole