Due to the nature of most tubs being less than glass clear, the snake may feel less exposed and safer to explore it's home. Like Connie mentioned sometimes it takes them awhile to go into their hide when it's placed in a new home (or a whole new hide). I've actually showed some of mine their hide by pointing their head that way and it's like..."oh well there's MY hide!" and off they go in it.

Just watch the snake, observe quietly and watch for patterns. That will likely give you tons of information about what your snake is up to in it's new home.