It appears that many of the cars involved in this wreck uploaded daschcam footage and some details, you can find them in the comments of the linked video. Says that there was coolant on the track and a dead car, possibly the one parked in front of the BMW in the posted video. He could have possibly got around the spill and the stopped car by going on the left side grass.
But it seems he wanted to warn incoming cars of the spill/pileup and get visible before the apex of the corner. There is dashcam footage of the orange/red GT3 that crashes into his BMW, and the corner is pretty much blind and very high speed, the GT3 looked like it was doing over 100mph and he had almost no time to react. There is also dash footage of one of the other porches that manages to get through after the red GT3/Skoda crashed, and there are about a half dozen cars piled up maybe 50-100m beyond the BMW, that is another thing to consider.
Im going to give the guy the benefit of the doubt, track officials/flagging seems sparse on the ring and it appears he did what he thought was best given the situation. He could have driven through the grass and away, but I think he wanted to at least attempt to prevent what happened to his car from happening to the pileup.
