I had a cat rip a hole in the bottom of a box spring on my bed and climb up into it to sleep, so she wasn't on or beneath the bed but inside it. And on his first day here, Theo managed to get inside the back of my recliner chair -- the back panel of leather gapped out when the chair was reclined and closed up again when the chair was upright. I could hear him crying in there, but I couldn't figure out how to get him out at first!
I don't know if anything like that is possible in your house.