Especially your example with "run over elementary school children" is duplicitous. They showed how much less dangerous the impact from the Waymo was.
That'll depend on the circumstances. If someone is killed because of a mistake a human wouldn't have made (like driving into oncoming traffic or down a light rail track) it'll be entirely their fault. Even if they do something humans sometimes do but never should like running a red light I'd argue that it makes them unsafe. To our knowledge they've only been involved in one human fatality so far but it wasn't their fault so I don't blame them for that.
For example, here’s a case where a human did it to avoid an ambulance:
https://www.click2houston.com/news/2012/09/18/10-injured-in-...
This guy says he was blinded by the sun:
https://kutv.com/news/local/trax-train-hits-vehicle-in-sandy
Sometimes people are drunk:
https://komonews.com/news/local/police-suspected-drunk-drive...
I was skeptical about the guy who claimed to be "blinded by the sun" and searched for more info only to find that people get hit by the light rail in Sandy Utah with alarming frequency. Not even just in cars. Pedestrians, people on bikes, people in wheelchairs, I'm starting to think it's cursed.
They should have done that flood training when they weren't putting people's lives at risk. It's not as if this was a situation that no one could have anticipated would arise. Over half of all drownings in a flood happen because of people driving into them. They're just lucky that they stopped service before they had more blood on their hands, but the fact that they were willing to experiment on the public first is concerning.