[Good thing no one's asking! Or rather, would it make any difference, even if someone did? She'll probably keep smiling if he tells her to her face she's being tryhard, as rude as it may be. Still, it's probably not that hard to imagine?]

Thank you for your understanding, and it's okay, I've already eaten. [He's offering out of politeness too, so she bounces the offer off with the selfsame polite smile.] I wouldn't mind making small talk and try answering questions you may have in the meanwhile, but I don't want to disturb you eating, either. Hmm... What do you think, mister?