During the first annual GG2H rally somewhere in the middle of nowhere, California, a Switzer P800 Nissan GT-R ran off the road and rolled down the hill. The C63 AMG following them pulled over to assist, but pulled up into an area of dry brush, which was ignited by the heat from the brakes. The whole car plus a good chunk of the hillside roasted to a crisp.
Luckily all the occupants survived with minor injuries in the Nissan and none in the Mercedes.
Thanks to Ben for the info!