2011 Le Mans Series at Le Castellet - Pace car Ruins Everything

What a Disaster at the 2011 Le Mans Series at Le Castellet!
Almost immediately chaos ensues as a result of the pace car not doing as it was supposed to:

Apparently whats happened here, is the Pace car (Audi RS5) was supposed to leave the track when the lights turned green so that everyone could go full throttle, unfortunately the driver of the pace car (for what ever reason) chose to remain on the track, and while the front row of drivers noticed this and slammed on their brakes, the middle and rear section of the pack had no clue and began slamming into the back of other cars while everyone in front was putting on the brakes!

Edit: It seems likely that this may also have something to do with the light operator, as has been pointed out by some of our astute readers. Because the yellow flag was still waving, for a car that had stalled on the track, the light should have never turned green like that.

A number of cars were damaged in the wreck, including 3 of the front running Porsches are out of the race before the race even began.

Also, Wtf Aston Martin @ 2:56 in the video, a sticky throttle problem?