Please Note: Pablo is not stuck, nor had he been forced into the cat house. Do not be concerned, he has since gotten out.
I am not sure what state of denial he is living in that lead him to think he would actually fit in here. I am sure that he believes he is fully inside. Not the case. It reminds me of the reason why we had to get a larger cat box. Our old one was a Pod-looking covered thing and Pablo would stick the front half of his body in, and instead of turning around and sticking his head back out so he could do his business, he would just stay with his head inside and his back end out and shit in front of the box.