What was the fire's fuel load then (if not pot contents)? timber countertop, nearby -cupboards?

I've personally never encountered such (the Al-pot bases usually survive, the sides sometimes erode away),
but would imagine (never having tried this at home) that an oil fire in an Al-pot
would melt the sides, not the base; as long as there is oil burning in a pot,
the base shouldn't exceed the oil's boiling point, and once the oil is done burning/evaporating,
what will be left to burn to heat the base (other than the hob...)?

Try some bush logic :
- Aluminium melts at 660C/1220F
- solid electric hob, or even a spiral- one, won't get there, gas hobs could.
- if direct-/convection heating by an incident flame, side of pot (closest to incident flame) will go,
- if radiation heat from above (i.e. flashover conditions), entire exposed surface of pot base will go
(but if pot is shiny most radiant heat should bounce off)