[ oof!! He actually does feel guilty the moment they say it - and looks even more puzzled than before. In what world is Lupin not thinking about the gem he loves? He knows himself very well, and he can recognize that, objectively, that's not much like him at all. He makes a grumbling noise, discontent, and crosses his arms. ]

... Something's wrong with me... Maybe. One of the most important rules of being a gentleman thief is to always have a plan, so why didn't I...?

[ HRRRM ]