She knows she should feel fear when the most feared man in the universe is calling for her arrest, but somehow Leia feels more anger than fear. Anger that the empire would stall a peaceful ship, fury that he would talk in such a way to a princess of Alderron.
Mostly, though, she's angry at that name. Traitor. All her life she's wanted to bring peace to the planets, and she's the traitor?
I am sure, she thinks, that Lord Vader was the real traitor back when the republic still existed. Who knows who he murdered to get where he is today.