Sluggo said:

No, no. You are clearly blinded by the love of the number 8. It has even infected your screen name!

If you are only going for an 'internal' answer to this non-conundrum, the room could have been shaped like an oval. Or the letter B. Or maybe the meditation chamber retracted into the wall while it was off screen. Or into the floor or the ceiling. Or it could have transformed into a autobot named kenobus prime and is out fighting the evil forces of the decepticons.

As for the viewscreen, my 'external' answer (which I will ALWAYS prefer over the 'internal' ones) is that the screen was behind the Emperor hologram as in the picture below:

I don't see this viewscreen

in this picture or in the following full-face shot of the Emperor.

Am I missing it?