He doesn't notice her there, at first, and when he does it's too late.
She's standing still, silent, her thin blond hair framing her frail, pale face, and her blue eyes are wide. She's never seen Gellert this angry.
Her hand is clenched around the arm of her favourite doll. She's never really grown out of dolls. He doesn't know if it's natural to be so attached to a rag doll, but he lets her keep it, because he doesn't want to get her angry.
Not that he cares, at the moment. He's too busy yelling at Gellert.
And Gellert is beautiful when he's angry. Anybody can see that. Gellert is beautiful and dangerous, fearful in his delicacy. He's everything Albus has ever aspired to be and more. But there's also something slightly…off about him, something that doesn't quite fit in Albus' idea of a perfect friend.
And Ariana stands there, in the doorway, watching in silence. He doesn't notice the fire in her eyes. He never pays attention to her eyes; they always unnerved him. They are so piercing, so pure, so blue…it's like they can see into his very soul.
Wands are drawn. He's too focused on the fight, on the pain of betrayal, to notice her. She's paler than ever, her body shaking. The doll's hand is crushed in her iron grip. He sees flashes of green all around him, hears the voices of his brother and his friend shouting over the crackling of the spells.
He doesn't hear the scream.
And as Gellert runs, Albus turns to see her.
She's lying still, silent, her thin blond hair framing her frail, pale face, and her blue eyes are wide. He's never seen Ariana this motionless.