I have seen the horrifying film of this incident, and I never want to see it again. Remember an Italian marshall was killed at Monza just a few years back, so it's not totally a thing of the past.

I too have driven that bit of road many times Richard, once even driving a Coombs tuned 3.4, and I never did understand how that accident happened, but happen it did. Incidentally the Coombs jag wasn't mine, and it was undriveable in the wet, with normal tyres fitted.
BTW Richard, you may remember that Coombs garage wasn't that far from the scene.