Glad you have a somewhat positive followup report for us. Scary.
I was in a crit (Copper Mtn. Colorado) that narrowed 50% 100m after the start finish. There were hay bales on the side. Everyone was great about giving room for everyone else to get to the middle in that section. One lap, I was 2nd from the left, moved to the middle, and could just feel that the guy on my left didn't follow me. We were doing 30mph, and I barely got a chance to look back at him, to see him struggling to get his bottle back in the cage. BAM! He slammed into a wall of hay bales. The ambulance hauled him away within 2 laps. Horrifying. No idea what his injuries were though.
It looks like that rim might have failed at the weld. If so, I would contact Mavic, at the very least so they can analyze it and see if there's something they could do to prevent it in the future. It's tough to say what caused the initial failure, but the rim should not be cracking at the weld -- as the weld should be stronger than any other part of the rim. The other rim buckles and cracks appear to be at spoke holes, as you would expect.
It's tough to tell from the photo though. I could be wrong about the weld.
Scary stuff though. Thanks for sharing -- I guess
