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In his lightsaber duel with Vader on the Death Star II, Vader throws his saber at the scaffolding Luke is on. This causes Vader to lose track of Luke.
While he searches for Luke, they have a short conversation. Luke is standing still, apparently hiding in dim light.
Vader can also sense Luke's feelings and realizes that Leia is his sister. When he says that she will turn to the dark side, Luke emerges with a speed that suggests he was crouching down…behind some stairs a few feet away from Vader (his cloak seems to be in the bottom right of the screenshot).
The choreography here has always confused me because there doesn't seem to be anything under the staircase to hide under, nor does there seem to be as much darkness as the earlier shots suggest. Further, Luke emerges just a few feet away from Vader in a direction he was looking a moment before. How did he miss Luke under there?
How was Luke hiding in his duel with Vader on the Death Star II?