I've seen worse accidents caused by safety car mishaps.
Fortunately the driver, Tetsuya Ota, wasn't killed. This crashed sparked a lawsuit by Tetsuya Ota against the track for sub par marshals, which, because of their actions, his melted helmet burned his face. This crash pretty much ended his professional racing career.
What happened was that the safety car was traveling a lot faster than it ought to have been in the wet, and it suddenly slowed down, which caused a Porsche to aquaplane and crash into a BMW ahead. Same thing happen to Ota's Ferrari, and it lit up on impact.