"Second part. I would be entirely willing to help at any time." The impromptu and interrupted 'assistance', back in the clinic, would have been enough to convince him, even if Bo hadn't been charming company when not starving. Besides that, she was right: he was one of the best options, because he could stop himself, stop her, and it would probably be harder for her to kill him in any case.

"For the first... is it possible to convince you to switch that to me as well? I assure you I'm far more likely to make a clean go of it. He'd do it, but it would be a protracted messy business while he tried to 'save' you first." He'd do it, yes, but Thor would feel terrible and guilty forever.