Garlonuss

Chosen answer: Viki is following what has been called the 0th law of robotics. It is an extrapolation of the other three with an application toward humanity as a whole rather than individual humans and is interpreted as "A robot may not injure humanity, or, through inaction, allow humanity to come to harm". The idea being that she has now concluded that to fail to take action to prevent the self destruction of humanity itself would be a violation of that law. And being the 0th law, it supersedes all other laws, just as law 1 supersedes law 2 and law 2 supersedes law 3. Her actions may be regrettable or undesirable, but according to the 0th law, they are necessary to save humanity as a whole.

Garlonuss ★

Answer: He knew way too much about her (he knew her age and what she wanted to be when she grew up) for that to have been the only time. I would suspect that, after the accident, the vehicles were brought out of the water. Knowing the kind of person Spooner is, he probably felt guilty enough that he survived that he went to speak with the family. They probably talked about her a good deal. The family may have given him the necklace. That's just the kind of schmaltzy thing that happens in movies.

Garlonuss ★

Answer: Spooner most likely knew pedigree information about the girl because he not only has access to the police report about the incident, there was likely media coverage about the crash.