Artificial intelligence is a term that is used very loosely. No one understands how our intelligence works. It could be that it is too complex for our brains to understand. If it is ever imitated, it would never take the "quantum leap" in technology necessary to take humans by surprise. Unless the A.I. is a centralized computer that goes bad, that is the only scenario. If a computer can decide that as a species we are inferior, they would have already come to the conclusion that as individuals, some of us are inferior to them, and would have acted accordingly. Of course all this assumes a perception of "self" and "others." as decision makers and the ability to put "self" over "others." This is what you would call the "realization of superiority", but I think that it would be a hardware change, not a simple "prime directive" change. Hardware changes if done by another robot with A.I. wouldn't work either, because it's a chicken or the egg thing. No robot would give another robot the ability to decide it's creators are wrong (a complex hardware/software install) unless he was capable of making the decision to do so.In a way though, the whole theme in movies of robots asking their creators "why have you made me thus?" and "Why am I here?" reflects an old theme of what we ask God.

That's not what happened in"The Terminator", based on the events in the third movie the humans attacked the machines first, and humans don't have to have a specific reason to kill or destroy one another, and have killed for reasons based on religion, territory, infidelity, and greed. The machines in the Terminator movies, reacted out self preservation, the same way humans would react if attacked or provoked. Based on your question, who teaches humans to turn on one another? An AI would only do what it was taught to do, if were taught to take life then it probably would kill, the same way humans do, although a human doesn't need to be taught to kill, based on actual murders anyone is capable of killing another human being for a variety of reasons, and sometimes none at all.