The companions can be taken over by AI already in certain situations.
If you're wielding the Shattered Flail, for instance. You have a chance to go mad, at which point the AI takes over your character. (which will almost result in that character using a sleep potion)
If you sacrifice one of your companions to the kua-toa fish folk then the AI takes over that character.
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I'm not saying that any of that means what you're asking for is possible. I don't know. But it's probably worth pointing out that such things exist in the game currently.
