Zara’s description of Tamra as “that Uncle Tom Tamra woman” references the 19th-century American novel
Uncle Tom’s Cabin by Harriet Beecher Stowe. An “Uncle Tom,” referencing the book’s title character, is a Black person who betrays their cultural or social identity to be excessively obedient toward or accommodating of white people and white culture. So when Zara calls Tamra an “Uncle Tom,” she’s suggesting that Tamra has betrayed her allegiance to her Black racial identity to achieve success among the predominantly white, privileged society that people like Alix inhabit. This moment is also important because it’s the moment that Emira realizes that Kelley has been right about Alix all along.