I completely agree that Kryton's motivations, such as they were, did not cut it. It felt thrown-in and out of place, somehow. He's been bowing, kneeling and answering Elaan's orders like a good boy and that's all we saw of this "relationship" with her. It almost seems like she's just making it up. Would it have killed "them" to show the two alone, having their little moments where he could at least say that he's been working on a plan to ruin this mission, but he won't tell her more to keep her protected.