Channel72 said:
There is a very strange, almost serendipitous scene in Empire Strikes Back that has always fascinated me. It happens after the scene where Chewie flips out and starts attacking Storm Troopers just before Han is about to be lowered into the carbon-freezing pit. Han intervenes and tries to calm Chewie down before things get out of control. While this is happening, Boba Fett aims his blaster at Chewie, but then Vader stops him from firing by pushing down the barrel of his blaster. Then - there’s this weird shot of Leia just staring at Vader for a few seconds. This is followed by a shot of Vader, seemingly staring back at her (although we can’t tell for sure because of his mask). Leia then walks over to Chewie and starts trying to calm him down. It’s the strangest thing, as if Leia and Vader instinctually exchanged some non-verbal agreement to prevent the situation from escalating further.
This moment had always intrigued me, too, especially since it’s underscored with a very ominous instance of the Imperial March that gives the impression This Means Something. I think I’ve more or less put it together thanks to the transcript of Irvin Kershner blocking that scene out from Alan Arnold’s Once Upon a Galaxy: A Journal of the Making of The Empire Strikes Back. (Excerpt: https://phantastiqa.com/unscripted-how-the-famous-i-love-you-i-know-scene-really-came-together/)
From that we can see: (a) Kershner wanted to make it clear the reason Chewie and Leia are brought there in the first place is so Han will “behave” and (b) Kershner and Fisher had great difficulty figuring out what Leia should be doing exactly before they take Han in to be frozen (at one point Fisher suggests she slaps Lando - and then she actually does it!).
I think Leia’s glare at Vader is meant to handle both those things. She’s realizing that Darth Vader knew Han wouldn’t cause trouble while she (she especially) and Chewie are there and that’s why they’ve been brought there in the first place.
I think it gets even cooler if you read into it further (and the scene makes it very easy to do so): Leia realizes Darth Vader knows Han Solo loves her. Like, he can sense it with the force and shit. And it confirms for her that Han isn’t just attracted to her or just “really really like” her, he’s seriously, genuinely, deeply in love with her. And I think here is where she goes from “attracted/ really really like” Han to being in seriously capital-L love with him herself, and admits it to him. And his “I know” response doesn’t bother her, because she also knows he loves her, too.