The only thing he would potentially overheat himself for was Pandora. That brief chance at freedom, however slim it might have been, was thrown away the moment he realized that it would require throwing her away to do so. Across all these years, he has never once reconsidered it and never once resented her for it. They were created as a unit - a pair. The only thing that the other had in the face of the horrors they'd been forced to live through and to commit.

Prometheus notices the very small cue from Rinzler; the program was uncertain, thrown off by this sudden change in attitude he had towards his sister. That's fine. Reassuring, even, that someone who knew him from that high school could not tell that he was bluffing about this supposed calm in the face of being completely separated from her for the first time ever. Thinking about it sent his circuits on edge.

So when Rinzler does his usual thing of running away from upsetting topics, Prometheus doesn't bother calling him out on it. After all, he wanted a distraction, not another overt reference to his missing half.

"Who knows? Develop something for the ship's defence? Ha! What do we need protection against? Honestly, you'd think they'd give me a bit more information....

But, well... It doesn't feel like this ship, it's captains and I are going to be getting along any time soon."