Never mind Rover, he's got ambitious tendencies! No it's the curtains which draws my attention. The size of the wall screen changes size throughout the series, but someone has been arranging the curtains to resemble those of an actual stage!
"All the world's a stage
and all men and women are merely players
They have their exists and their entrances......."
And Number 2 has just made his, although he has been here before, and is not at all happy at having been brought back. But now he has made his entrance, he'll have many parts to play. So I suppose to have the curtains around the wall screen like that is very apt.