If the only place he could still be in the wall, then guess where he is. If he's eaten the past couple of days, I doubt a rat laying out would entice him any time soon. I leave it near the hole though just as a confirmation of where it's at.

You know as well as everyone else he could live in that wall for quite awhile. In the mean time double check everywhere else in the home really good, including in between sofa cushions and closets (i have large speakers collecting dust in my closet, found my bp there one day).