I think you misunderstood me, or I just wasn't explicit enough. I was talking about humans being burned by natural things other than flames. From my (admittedly limited) experience, being burned by a flame or by a hot surface or a hot liquid isn't qualitatively different. Even sunburn (the aforementioned exposure to sunlight) feels similar if bad enough.
Got it, yes-- I definitely agree that a sensation can be cross-triggered by conditions other than the evolutionary pressure conditions.
Is there a "dangerous heat" environmental candidate for lobsters that we can speculate could be sensory-cross-triggered by boiling water? Underwater lava?
