You're not the Malnosso. [She answers it simply, but it's an easy discernment for her to make as she watches him curiously. And he's right. She wouldn't appreciate knowing about that threat at all.]

The Malnosso do not show up after their Shifts being honestly remorseful, regretting what they've done to us, seeking forgiveness. The Shifts they put on us are intentional, experimental and they do them with the full knowledge of the consequences and pain they will likely cause.

From what I've gathered, you and Teddy were taken by them before this all started and you both endured something terrible, considering how he looked when he first got back and what you came back as. You love him. It snapped your control. You... If there's one thing I can understand, it's the loss of control after something like that. And something I know a good many others can as well. It pushes us over lines we would never cross otherwise.