He clearly liked being under his dish...lol BP's are fairly docile, private and gental creatures. I think like the other poster stated....you just stressed him out. You moved his stuff (as I have one that loves her set up to stay the same and when I clean her cage....she looks annoyed and has to redo stuff). Maybe it was his way of telling you....I'll do what I want to do...don't push me". Also seeing how you don't know his history...he might not of been handled often. So maybe he is just getting use to it. Either way...I would not worry about it.