I just had a look at the corridor on Bespin, and I see it now. I missed it the first time because it almost seems like they turn 90 degrees before opening the door. Tricky... but not impossible.

It looks like Vader is meant to be deflecting the blaster bolts. One shot, from behind Vader, shows a bolt hitting his hand, sparking, then another light flaring up on the wall by the door, although the blaster bolt is never seen going from hand to door. There's also another burn visible on the other side of the door, presumably from one of the previous bolts.

DE