Yeah, Cyrus really isn't ready to talk about Luzi.

Aha, you were all tricked! For it was not Cyrus writing the letter at all - it was Veld, making her first actual on-page appearance outside of flashbacks and extra pages. Veld has the unique ability to posses objects (and people, if they're unconscious) and move them around; in exchange, she can't manipulate anything with her hands.