Three thoughts. No more, no less.
I think that Luke was drawn to the Chamber from the moment he entered Cloud City and the Force was guiding him there. When I was younger, I always thought it was such a nice coincidence that Luke happened to stumble upon Vader right away, but as I grow older I have begun to think differently. Luke claimed he was running off to Bespin to save Han and Leia from what he saw in his vision, but he was so willingly drawn to the Chamber. I think Yoda and Obi-Wan knew this would happen and knew he would face Vader.
I like how the script describes Luke as feeling “confident” and “eager” to confront Darth Vader and I find that to be a bit foolish of him. I have to keep in mind, though, that this is his first confrontation not only with Vader, but also since he’s started his training. And I believe Vader knows that Luke is feeling overconfident so he jabs him with the statement that he is not a Jedi yet. Ouch. It’s like preparing so hard for the Olympics, only to be told you aren’t really professional yet.
The last thing about this scene that always made me angry was the fact that Luke attacked first. Jedi do not engage first! Why did he do that? Did he sense an attack? Did he know the attack was inevitable? Does it show that he really is not a Jedi yet because he can’t have patience? Was he just dangerously close to the dark side in this moment? Was his overconfidence his weakness? This part has always bothered me. I understand in ROTJ when he attacks the Emperor…clearly the Emperor was goading him on and making him angry. I guess I just don’t understand why he would attack Vader when he is fresh off of his training. Now, keep in mind, I think there is difference between igniting your lightsaber and attacking with it. I feel like igniting is being on the defensive, being prepared. You could argue that just by igniting it you are welcoming an attack, but I still don’t think a Jedi should go on the offensive. Even Yoda said earlier in the movie, “A Jedi uses the Force for knowledge and defense, never for attack.” Tut, tut Luke.
INTERIOR: CLOUD CITY — CARBON-FREEZING CHAMBER — ANTEROOM
Luke cautiously walks forward among hissing pipes and steam. Seeing an opening above him, he stops to look up. As he does, the platform he stands on begins to move.
INTERIOR: CLOUD CITY — CARBON-FREEZING CHAMBER
Luke rises into the chamber, borne by the platform. The room is deathly quiet. Very little steam escapes the pipes and no one else seems to be in the large room. Warily, Luke walks toward the stairway.
Steam begins to build up in the chamber. Looking up through the steam, Luke sees a dark figure standing on a walkway above him. Luke holsters his gun and moves up the stairs to face Vader. He feels confident, eager to engage his enemy.
VADER: The Force is with you, young Skywalker. But you are not a Jedi yet.
Luke ignites his sword in answer. In an instant, Vader’s own sword is lit. Luke lunges, but Vader repels the blow. Again Luke attacks, and the swords of the two combatants clash in battle.