She stays with her son because he needs her, needs Lily there because he's young and frightened and he's being told he's a human sacrifice. Her eyes are still full of fire as they stare at Dumbledore. "Chosen one? Chosen by you to do your work, more like."

When Harry speaks though her breath stutters out of her and for a moment she doesn't respond, burying her face into his hair. "Harry," she whispers, "none of this is your fault. Not a single bit of it. I need you to know that. You're not ruled by some pre-ordained destiny and even if you were it wouldn't be your fault. When things happen, the fault lies in the people that do those things of their own will." She kisses his hair, not moving. "It's his fault, not Harry Potter's."

She knows the others will be arriving very soon and so she straightens, hand gently squeezing Harry's arm before she moves to Dumbledore's desk, placing both hands on the surface of it flat. "Albus, you know that prophecy is about interpretation. If he'd chosen another child, they would be in this office instead." A breath. "And the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not." She has it memorized. Word for word. "Do you know what my son has that he doesn't understand? He has family. He has love. He has me. If you think I'm going to let you send my son to battle, you're wrong. The power to vanquish the Dark Lord is the people around Harry, protecting him and by proxy everyone else."