Until you know what actual terms are to be subsituted for A, B and C you can't say if its fallacious or not.
"If a person can run 10 km in half-an-hour, that means they won't get breathless walking up a 20 metre rise" seems sound to me, not a non-sequitur.
@Manbearcat gave similar examples upthread. He also made the point that, given that we're working in the realm of speculative fiction, the constraints on inference are about genre, folk sensibilites, etc, and not empirical fact. You see this in action movies where the fact that someone can fly a helicopter typically
does mean that they can fly a fighter jet; the fact that they have legs typically
does mean that they can ride a horse; etc.