While that particular scenario may not be likely, I'm increasingly inclined to think that people being scared by Terminator is a good thing from an existential risk perspective. After all, Musk's interest here could easily lead to him supporting MIRI or something else more productive.
It's not only unlikely - what's much worse, is that it points to wrong reasons. It suggests that we should fear AI trying to take over the world or eliminating all people, as if AI would have incentive to do that. It stems from nothing more, but anthropomorphisation of AI, imagining it as some evil genius.
This is very bad, because smart people can see that those reasonings are flawed and get impression that these are the only arguments against unbounded developement of AGI. While reverse stupidity isn't smart, it's much harder to find good reasons why we s...
http://www.businessinsider.com/musk-on-artificial-intelligence-2014-6
Summary: The only non-Tesla/SpaceX/SolarCity companies that Musk is invested in are DeepMind and Vicarious, due to vague feelings of wanting AI to not unintentionally go Terminator. The best part of the article is the end, where he acknowledges that Mars isn't a get-out-of-jail-free card any more: "KE: Or escape to mars if there is no other option. MUSK: The A.I. will chase us there pretty quickly." Thinking of SpaceX not as a childhood dream, but as one specific arms supplier in the war against existential risks, puts things into perspective for him.