Watchman Goby won't go back in his hole

Hi! We've had a pistol shrimp & watchman goby pair for approximately 9 months. They were active & seemed happy. Lately, the pistol shrimp has been snapping a lot. We suspect he's fighting with bristle works. Anyway, tonight my husband injected some apistacia with boiling water. When he did, our yellow wrasse hid in the sand. Shortly thereafter, the goby came out of his den & hasn't gone back in. The wrasse is back out, but the shrimp appears to be missing? The holes to their den have covered up with sand & the goby has been all over the tank for the last couple of hours in a panic. He is now resting on the sand. No one bothers him, so we assume he's safe, but we can't figure out what happened. Will he make a new home for himself is the shrimp is gone? Thanks!