Is my Bullseye pistol shrimp attacking my threadfin butterflyfish?

So I just added a threadfin butterflyfish to my tank, and he keeps going into my bullseye pistol shrimps lair. And when he does my pistol shrimp looks like he is attacking him but my butterflyfish just stays still. However my pistol shrimp isn't cocking his claw or clicking to scare him away. I have wondered if he is just cleaning him but im not sure. My threadfin seems unharmed any help?:fish: