lodger removal.

I've been checking the reef since my last posting and finally narrowed the
shrimp location, this afternoon when I finished work I came home to find a
small pair of beady antennae staring at me out of a hole in the rock. I
took it out and have the rock in a plastic container but I cant get the
shrimp out. I tried a syringe full of boiling water but it retreated
further into the rock and later on after another attempt it came out and
punched the needle of the syringe.
I even tried a little bait but it still wont leave the rock.
the trap idea is sound but if it wont venture out then I'm stuck. this was
my only successful colony of yellow polyps.
any ideas or practical experience.

Robin.