Spoilers are ahead for the Mr. Robot Season 3 premiere. For perhaps the first time in the history of Mr. Robot, the distinction between Elliot and Mr. Robot is very clear. That means that the other characters' intentions with Elliot are more clear as well. And though the Season 2 finale hinted at it, the Season 3 premiere confirms that Angela is working with Mr. Robot and the Dark Army unbeknownst to Elliot. Along with believing that Tyrell did the right thing by shooting Elliot to stop him from ending stage two of his plan to bring down E Corp, she is now conning her friend over the long haul for the Dark Army. While he is unaware of it now, Angela is betraying Elliot's true self on Mr. Robot, and their relationship is now defined by this manipulation.
As Elliot notes in "Eps3.0_power-saver-mode.h," Angela is the only person who can tell when Elliot is himself versus when Elliot is his father-like alter ego, so he requests that she keep him in check. But instead, she is secretly working with the Dark Army to manage Elliot by joining forces with the Mr. Robot side of his mind. If you can't understand why Angela would deceive Elliot like this, she explains it herself: Whiterose inspired this betrayal. While Angela didn't have confidence in the schemes that Elliot as Mr. Robot conjured up with fsociety to bring down E Corp, she believes that Whiterose and her Dark Army do have the power to succeed, which will lead Angela to get justice for the death of her mom. So rather than help Elliot overcome his secret and destructive other side, she's now feeding into his delusions against his will by supporting Mr. Robot.
It's complicated since, as Angela admits herself, Mr. Robot really is just Elliot. So while Mr. Robot tries to make Angela feel guilty for working against the real Elliot, she can justify it since she is interacting with Elliot the whole time. As the clever camerawork on the bus shows, she always sees the Rami Malek version of Mr. Robot — never the Christian Slater version.
However, if she was honest with herself, she would acknowledge that she is backstabbing him, since the real Elliot trusts Angela implicitly to help him not give into his dark side. The real Elliot has a conscience and doesn't want to cause the destruction that Mr. Robot does. And Angela knows that, but she is disregarding it for her own purpose. Another reason it's particularly cruel is because Angela is knowingly manipulating Elliot's emotions. He feels a special connection to her and loves her in his own way. Yet, that doesn't appear to matter to her now since all she wants is vengeance.
Season 2 saw a major shift in Angela — an ambitious, ruthless shift. And although her motives were hazy last season, Whiterose emboldened her and her focus is now as laser sharp as ever: to destroy E Corp for killing her mother. The best way for her to achieve that is by acting as the facilitator for the Mr. Robot version of Elliot so that he can complete his plan, and she doesn't care if she deceives Elliot and Darlene in the process.
Angela's actions are upsetting on a character level, but it's an exciting turn for the series overall since the audience now knows when other characters are working hand-in-hand with Elliot's subversive mind. Rather than just be in Elliot's head as he grapples with his other personality, Mr. Robot is painting a clear picture of what Mr. Robot does when Elliot's consciousness is not in control. So while Mr. Robot may have stopped talking to Elliot, he's in very close communication with Angela. That means that Elliot has put his trust in the wrong person, and leaves only Darlene to save Elliot from himself.