I interpret 3 as the chat bot requires no prompt from a human. Imagine the chat bot wakes you up in the middle of the night saying, "Hey, sorry to disturb you, but I was thinking... wouldn't eliminating all humans help to reverse the climate crisis more quickly? Just a thought." That is what I think of as number 3 (not actually wanting to kill off humans, but it is thinking on its own, without any prompts and then choosing to share what it has been thinking about with a human).