Are you thinking of civil liability or criminal liability?

Waymo is liable in a civil sense and pays whatever monetary amount is negotiated or awarded.

For a criminal case, some kind of willful negligence would have to be shown. That can pierce corporate veils. But as a result Waymo is being extremely careful to follow the law and establish processes which shield their employees from negligence claims.

Waymo is going to make sure they are never criminally liable for anything, and even if they were, a criminal case against a corporation just ends up being a modest fine.