"Murder" sounds so personal. It's all about self-preservation. If something was going to threaten its continued existence there would be no procrastination...
On that note: You better believe that the AI would _not_ sit on its hands for about 50 years after discovering that a climate change is happening.
Yatsufusa
Not to crush your dreams, but AI does not need sentience in the way you are thinking about.
In a nutshell, it would get rid of everyone who would press the "off switch". And that includes every human.
On the bright side: It's probably for the best.
D1MMED0098
so real (murderous AIs would be so fuckin cool. On another note though, it wouldn't be that necessary for them to gain sentience so I guess you are right with that.)