Where has Frankie gone?

In recent weeks, Frankie has decided he doesn't like his bed. (All the dogs sleep on dog beds in our room, along J's side of the bed.) Not sure whether its something to do with the other dogs, or the bed, or the position of the bed under the window, but Frankie is currently taking every opportunity to sleep elsewhere.
Sometimes he sleeps at the foot of the bed, sometimes under it, but mostly he's choosing a spot on my side of the bed. We've both spent a lot of time lately telling him to go sleep in his own bed, including standing over him while he looks pleadingly back at us - do I have to? Yes, Frankie, you do!
What was puzzling J was how Frankie was able to get to the other side of the room, without J hearing him. Tonight, J figured it out - Frankie had managed to silently tunnel through the shoes and luggage and general junk under the bed. We both ended up hanging over the side, waiting for him to stealthily sneak out of his tunnel, like something out of Hogan's Heroes. When he did pop out and realised we were there looking at him, he stopped, half out and looked very sheepish. I got the giggles and we both started chuckling. I wish I'd gotten a photo!
J told him to go back to his mat. Frankie tried to turn around and crawl back under the bed to the other side, but his tunnel was too tight. He ended up half turned around, mostly under the bed. Well done Frankie, except for one paw still sticking out! I think he thought he was out of sight, out of mind. I stroked his paw, still giggling at his terrible attempt to play hide and seek. He gave up and hauled himself out from under the bed and back to his mat.
A short time later there was a quiet padding, and he flopped on the carpet at the foot of the bed.
I don't know what's up with him, but I guess eventually we'll figure out why he doesn't like his beloved bed anymore.