I wonder if he had locked up the tire and was skidding on the sidewall---I have eaten 90 percent through a tire's tread---the thickest part-- in a severe lockup so it seems possible to me that a couple seconds sliding on the sidewall might have torn it enough for the 100-psi tube to squeeze through and any contact with pavement then ... would leave us where we are now.
I always like to hear a crash story that ends "... so I picked up my bike and rode on " ... Particularly when it starts "I was descending at insane speed .... "
So, thanks for surviving to entertain me.