Funny thing About Asimov was how he came up with the laws of robotics and then cases on how they don't work. There are a few that I remember, one where a robot was lying because a bug in his brain gave him empathy and he didn't want to hurt humans.
In the Foundation books, he revealed that robots were involved behind the scenes, and were operating outside of the strict 3 laws after developing the concept of the 0th law.
>A robot may not harm humanity, or, by inaction, allow humanity to come to harm
Therefore a robot could allow some humans to die, if the 0th law took precedence.