"The Intelligence Explosion Thesis says that an AI can potentially grow in capability on a timescale that seems fast relative to human experience due to recursive self-improvement. This in turn implies that strategies which rely on humans reacting to and restraining or punishing AIs are unlikely to be successful in the long run, and that what the first strongly self-improving AI prefers can end up mostly determining the final outcomes for Earth-originating intelligent life. " -- Eliezer Yudkowsky, IEM.

I.e., Eliezer thinks it'll take less time than it takes you to hit Ctrl-C. (Granted it takes Eliezer a whole paragraph to say what the essay captures in a phrase, but I digress.)