i don't think brian rolled. it looks like brian got out of his lane and caught Chief in the 1/4, essentially pit maneuvering him and he rolled once he got sideways. went over the curb, through a fence and down into some rocks.
Yes 8th mile. crashes happen at the track or the street. Daddy Dave just destroyed his new car a couple months ago at a track. the "street racing" on the show might as well be a track, you can see the medics and safety crews in the backgrounds of some of the races. Accidents happen when your playing with big big power toys.