So here's what we've been able to find out:
Mercedes-Benz organized an 'SLS AMG Track Xperience' day on the Zhuhai International Circuit in China. Ok, sounds like a good time, but the day ended badly for a pair of Chinese auto journalists. Details are still shaky but according to Car News China, the accident happened when the SLS driver slammed on the brakes a bit too early when going through a turn - on a wide open, traffic free track (in what looks like good weather conditions).