While I don’t know exactly what happened here, if the pan was dry or all the moisture was cooked out of the food, there isn’t really much to dissipate heat.
If this pan was a cheap alloy, it was possible that it had a low melting temperature. If the stove was on high, the pan will eventually get as hot as the stove allowing it to melt or at least, collapse under its own weight.
Non-stick pans tend to be made of aluminum (660°C melting point), sometimes alloyed with some copper to improve thermal conductivity. Aluminum-copper alloys tend to melt in the 500-600°C range. Most aluminum alloys melt at a point which an electric stove can easily reach if left on high. The coils can glow cherry-red pretty easily, which is 815-870°C.
Lulz. I was reminded of the conspiracy theory “jet fuel can’t melt steal beams”, for some reason.
(While that statement is technically true, metals can get extremely soft while they are heated close to their actual melting points. You know this, but it’s surprisingly easy for many to overlook this basic fact because of the specific data on melting points and such.)
Thanks for filling in the gaps, btw. Data good. Nom.