Well, like i said, did he do this stuff or move weird when you examined him at the pet shop? Also make sure you dont have it too hot in there as i assume you got heat tape on the floor of the tub under the hide? Too hot coupled with no other hiding spot can overheat the snake. Snakes arent exactly the sharpest tool in the shed sometimes and will sometimes sacrifice their welfare of being too cold or too hot in favor of a secure hiding spot.