Meh, be fair to the op, mtb racers don’t often have mass pile-ups like roadies do – where the front of your bike might ram the leg of a guy in the road in front, though there are plenty of sharp/stabby bits of a bike already
Not sure why P-R, of almost all races, needs discs though, especially in a “dry” running – no real descents, very slippy surfaces where even accelerating hard could make you skid, …
Seems very little info on the true nature of the injury – not even a pic as far as I could see in 30 seconds on google. Do we “know” it was a brake rotor ?
Maybe they could engineer in a nice smooth, maybe thickened?, rim into road rotors – if genuinely necessary