Re: You had just one job!
On what we've heard here it certainly sounds as if the driver bears a heavy responsibility, but the underlying culture needs looking at too.
This being Uber, its a fair bet their 'safety drivers' are minimum wage peons, when actually they need to be highly skilled with very fast reactions because their job is to evaluate when action is needed and take it as late as possible.
Similarly the authorities will need to know if the drivers are just told to go out and sit there. or whether they are specifically briefed before each journey with a test plan.
And ye, as in the above, the authorities will also want to look at to what extent Uber monitor that their safety drivers are doing exactly that, and not sitting their watching videos. Bearing in mind the demands of the role it would not be inappropriate for the drivers to be banned from taking phones with them. Its hard to imagine an aviation test pilot having their phone with them!