"Luke! No! You can't do this!" she cries.
"It's the only way, Annabeth."
"But… but… there's got to be some other way!" she argues. "Athena always has a plan," she adds silently, tears running freely down her face.
He shakes his head. He's right, and she knows it. She gives him the knife, defeated.
Awaking, she lies in bed, sobbing. 'It's just a nightmare,' she tells herself.
Ten years later, and she still has the same dream every night. She's guilty, thinks she let him down. The logical side of her disagrees, but she refuses to believe it. And because of that, is haunted every night.
Yes, I know Percy gave him the knife, not Annabeth. Her brain doesn't agree with that, though. It's a nightmare. Yeesh.