And a bunch of monkeys ignore the "Stay Behind" safety chain.
Bingo. Best guess I read until this was when the strap or the hardware attached to it broke, it damaged the brake. Turbo encabulator seems the most likely cause.It actually looked like the caliber broke loose from the caliper mount and wedged between the wheel and the rotor. That's what caused all the sparks and the rotor to glow bright orange. Also, most likely one of the brake lines broke and splattered fluid onto the rotor and then ignited. Either that or one of the fezter valves cut loose and penetrated the muffler bearings causing the turbo encabulator to flambé the halogen fluid. Very dangerous.