She is stuck in two realities. On the one hand, she finally allowed herself to voice her regret. She is aware that she has committed terrible crimes. On the other hand, she hasn't addressed any of her false beliefs. She's still a fanatic, and it's impossible to imagine a universe where she gives that up.
Admitting guilt and abandoning your most deeply held beliefs are two very different things. Most people never make that journey. Their conviction softens. They make allowances for harsh truths they've observed. But over the years an individual's beliefs become a part of who they are.
Lydia has spent her entire life learning about the world and making judgments, filtering it all through a Gilead tainted lens. It's like when a child first begins to recognize objects when they're born--a ball, a teddy bear, or a bottle--all of the things and ideas that make up their reality. Her names for those objects and her notions surrounding them are all based on her fanatical viewpoints, and she's built up more than 50 years worth of this, adding new layers, burying them deeper and deeper into her being.
She would have to unlearn every bit of it. Forget learning to walk again; this is learning to think again. That process is impossible to fully complete. We see this in ex-fundamentalists and ex-cult members all the time. Brainwashing leaves an unwashable stain on the soul.
Janine sees this. Their kinship is completely one-sided. Lydia seems to have expected a tearful reunion, hugs, and a moment of joy--something to match the way she feels about the girl. Instead, Janine gets upset when she realizes that Lydia is angry with Esther.
Lydia says that anyone who would kill her sister deserves His retribution. Janine counters by saying that Esther was a child. She was hurt and abused. Lydia insists that she gave Esther a chance to live a life of service and grace.
Janine adds, 'Or else. Live a life of service and grace, or else you would let her rot in the colonies. I know you'd just pluck her eye out.'
Lydia seems hurt by that, but she quickly reverts back to her old rhetoric. 'I gave you the education you needed to live a safe and meaningful life, and here you are. Still with us.'
She's still deluding her. Lydia wants to change, but she honestly has no conception of what that means. Janine sobs, 'Just stop it. I know what you do, what you do to those girls. Your precious girls.'
Lydia's mouth drops open.
'I see you,' Janine goes on. 'I see who you really are. I've still got one good eye, remember.' She gives Aunt Lydia a look of triumph, shifting around in her hospital bed. 'You gonna take that one too?'
Lydia deflates, clearly troubled by Janine's words. She walks out. Remember, she's always wanted to believe that Janine loved her. When June told her how Janine felt it was like being stabbed in the heart. Lydia thought they had a special relationship. She is so far gone that it didn't even occur to her that her crimes would get in the way of that.
This is the first time Janine has ever been honest with Lydia. She was always subservient and sweet, seemingly innocent. She didn't show her pain. It was her way of pretending so she could survive. Now Janine doesn't care. She's injured and she's hurting, and she's finally telling Lydia how she really feels.
We don't know what goes through Lydia's mind when she leaves. She could be ashamed, angry, sad, or maybe repentant. She seemed to want to prove herself to Janine. That much can be safely assumed. But mostly she just couldn't stand to stay in the room any longer.