Raffy got out of the room again last night

I thought he had given up actually - now the board is well and truly hamsterproof. So you would think he would give up investigating. I maybe relaxed a bit too much and was a bit sloppy in putting it up last night and had it upside down. One side is flat and the other side is very slightly curved - so if I have it the wrong way up it doesn't sit completely flat on the floor. I also use a door stop to hold it up which isn't very strong (a stuffed duck!) and had stopped bothering to put the chair there as well thinking he couldn't push it over. Well he did!
I almost know within minutes when he's not in the room - it is just particularly quiet somehow. So I checked the board and sure enough it had been pushed over a bit, leaving enough of a gap to climb through - because it was the wrong way up.
As usual he had gone straight to the downstairs bedroom and was sitting on top of a floor sweeper next to the hamster treats drawer! Closed so he couldn't get in it.