This is obviously terrible, no one expects to go to an event like this and not come home. From my own experience, both doing this race and bike racing in general . . . there is nothing that’s going to be done that can keep a large field on a gravel road from crossing the center. Closing the roads completely isn’t an option, but probably a rolling enclosure for the pack is. As I recall there was only a large pack in the event I did for 10 or 15mi, at which point it was just shattered to small groups and individuals (Rasputitsa is HARD). No idea if that would have helped in this specific instance.