["You don't have to think of it as a debt!" Yes, she does. Or else she'll explode. The fact that Quetzalcoatl persists despite her rancid vibes is honestly so much to Rin. She's tired. Too tired to really argue continually. So instead she focuses on what she can manage.]

If you have other reasons, that's fine. But if someone is to be killed in my name I should be the one to shoulder that responsibility. I was too weak, and so I'll just have to find a way to make myself better. To make sure he can't do it again.