I think the biggest irritation for me reading the demons is that they have logic
But they can never take a second logical step.
yes, they don't "need" their arms to talk, but why would they talk if their arms are taken off? To live? If they know that you're a demon and you know that they know that you're a demon, do you think they'll believe you when you say you'll let them live if they keep talking?
Like, I feel like a way to stall solitar would be to simply ask "What have you actually learned of mankind? Please, tell me" and then each time she tells an anecdote, ask her to analyze it. "what does that story mean?" "what does that story tell you of mankind?" "What does that story tell you of what you should do?" etc etc etc.