That is frightening. Please followup with a post mortem. I would agree it looks more like an evap core failure. Has the system been recharged? If someone used R600 (Isobutane) or other flammable or counterfeit refrigerant, a small leak may have resulted in a small explosion in the confined area of the dash where there are plenty of electrical hazards. Otherwise the system may have been overcharged, but I would expect a hose failure before the evap core. On the bright side, you will have a prime opportunity to replace your heater core and evaporator with new and get to explore a junk yard for all the ductwork and trim.