It seems totally reasonable to say that AI is rapidly getting many very large advantages with respect to humans, so if it gets to ‘roughly human’ in the core intelligence module, whatever you want to call that, then suddenly things get out of hand fast, potentially the ‘fast takeoff’ level of fast even if you see more signs and portents first.
In retrospect, there had been omens and portents.
But if you use them as reasons to ignore the speed of things happening, they won’t help you.