I've looked at that a good few times now, bit of a "racing incident" if you ask me. At first I was thinking what the hell was the Ferrari driver doing getting in the way of the faster car, then it looked like McNish just barrelled into him, almost fogetting to brake/steer from another angle.
Fact of the matter is though, the Audi is a damn sight quicker car, and was approaching at a rate of knots. McNish was probably in the Ferrari's blind spot when the Ferrari driver checked his mirror, and before he could check again the Audi was there, on the apex of the corner too.
24 Hour racing is a great spectacle, and obviously a long standing tradition, but generally you see some much more horrific accidents because of the disparity in the machinery than you do in most other forms of (much more closely contested) motor racing. Reading stories of the old GrpC Jag's and Merc's of the 1980's barreling down the old Mulsanne straight at 250mph, trying to dodge Porsche 911's littered all over the place doing a mere 180mph, makes me wince quite frankly! 70mph is a hell of a difference if you're doing 70 when another car is stationary. When you're doing almost 4 times that already, the consequences don't bear thinking about.
Anyway, like I said, racing incident. Both drivers walked away thankfully and will live to race another day. What's shocking is the lack of effectiveness of the gravel trap (they work well for open wheeled cars like F1, but cars with enormous flat bottoms like LeMans cars just skid over the top), and the fact nobody stood behind the barrier got hurt! Until the car hit the barrier and came to a halt, looked for all the world like it was going to mince a whole load of marshalls and camera men!