Video evidence hasn't been released. I don't even know if it's been said what lane the Uber vehicle was in. It's possible she walked out from the center median and far enough that the impact would be on the passenger side of the Uber AV. But that would suggest she did so at a distance that the Uber vehicle could at least begin braking, even if it was still too late (in the same way train operators can hit the brakes despite it being way too late when first seeing a car on the tracks).