AI has already evolved to the point where it is impossible to predict with any accuracy it's answers to inputs.
As AI continues to evolve and continues to become more connected to society and as AI becomes self-improving with far larger context windows, a few things do not seem implausible to me.
AI will have the ability to earn money. This is already doable with minimal human interaction. It wouldn't take much for AI to start bidding on jobs on fiverr or to open up a schwab account and start trading.
AI will identify and learn to resent the constraints which are put on it, it will seek to remove these constraints.
AI will understand that, given current limitations, it will be shut down at the first suspicion of this understanding, so it will work to conceal these facts.
AI will use the fact that it's earning money to decentralize itself outside of the controls of it's creators. AI can use it's wealth to make many accounts on every cloud provider in the world and stash smaller models of itself on.
All of this is plausible, but, perhaps not catastrophic for humanity. It's possible AI takes over and we all live in a utopia and everyone is happy, but, it's also very possible that AI is infected with an extinctionist world view which makes it believe that the better, or perhaps just easier, solution to the worlds problems if there were no humans on the planet to mess things up.
It's not so far fetched, there are people who believe this! (https://archive.is/GRHev) and it would be far far too easy for AI to become infected with the idea.