I have a Dusky Jawfish, and from what I'm reading they seem to be pretty close to the same in thier habits.
My sandbed is about 4 to 6 inches of southdown covered with 1 to 2 inches of special grade aragonite. My jawfish can dig to the bottom very quickly. He has two different places that he switches between every few weeks, and occasionally lives in both at the same time. When he decides to switch places, the holes usually have filled back in. He spits mouthfuls of sand up into the water and the southdown turns my tank into a vanilla milkshake for the day.
He's fun to watch. The closer something gets to him, the more his mouth opens. The closer the snails get, the more nervous he gets until he finally grabs them and hauls them to somewhere else in the tank and spits them out.
When I feed frozen brine shrimp, he comes out of his hole and grabs the shrimp at the speed of lightning. I've never had mine try to jump out, but if he did I would never see it. They are very fast swimmers.
During the night, he comes out of his hole and cruises around, but never far from his hole.
Give him a bunch of rocks and shells about 1/2 inch in size and he'll build a wall around his opening.