"So you could have made it stop at any time. But you didn't." There goes Thellim's implicit model of the whole thing as some kind of sheer massive failure of intertemporal bargaining. "Why the iron clamps if you - if they didn't need to hold you down - I don't understand."
Thellim tells her Noticing Confusion detectors yelling 'I defy this data' to shut up long enough to hear this out. It's not going to be a lie, the literary conceit of this bizarre unreal world is obviously going to have whatever she hears next be the truth.