Bewy said:
I must say I agree with what Gorilla said, the idea of windows instead of balconies is interesting. And what's more I always found the rotoscoping of the characters quite ugly in this shot, but yet again the decision's all yours Ady :)

Well, the corridors in Bespin do wind quite a bit. My thoughts are they round a corner and are on a balcony. After this shot, they go down another winding corridor that masks the opening to the balcony in the background, hence no remaining visual cues of being outside. Rationalization to be sure, but logically, it works.