It's hard to feel the same level of ugly vindication when you're coughing up a lung. Anger, fear, spite, disgust, all swirl in Vanitas with no exit. Ventus turns to leave, and Vanitas's pain-hardened heart already accepts and fears and resents it.

'I'm sorry' pierces through it like a dagger, because beneath it all, Vanitas is a boy who's wanted that to be said from the moment he came into existence, even if it can never be enough. He wants what was done to him to be wrong, to have been ugly, instead of 'necessary' or 'for your own good', 'yes-you-should-be' warring with 'don't-dare-pity-me'. What comes out is a lung spasm that could be a choked sob, and Vanitas clasps a hand over his mouth, taking it away to force air back into his lungs in horrific fashion.

"Nightmares," Vanitas says weakly and strained. What does Ventus have to have nightmares about? Isn't his life perfect, or the illusion of perfect his full self fell for, made reality far too late?