Unfortunately, patience is the only thing I can recommend. I have also succumb to the temptation of moving rocks and you are correct in your thinking that it is more likely to scare them into more hiding. I would still recommend adding a fiddler sized crab if you can find one as they seem to be the universal octo attracting food but he/she will go after the hermit when she is hungry enough. Live shrimp will likely prove too difficult to catch.