I could argue that NOT attempting to save the man is a decision as viewed by the AI. That said if that is the case maybe also make it so that even auto triggers turn based mode and give you a round or two before they kick him in to make it a bit easier?
We might just have to agree to disagree here

My personal experience over a number of playthroughs has been that Smythin often dies before I'm anywhere near him, and the first time I see him he's already dead in the pit. Saving him every time requires metagaming, and I don't think we should need to metagame or save/reload in order to keep our oaths. And if the game is going to make oathbreaking through not being fast or good enough a thing, it should be way more consequential than this encounter.
Still, as long as Larian make a positive choice on how to handle this encounter I'll roll with it whether I agree or not, as long as it just doesn't feel inconsistent and buggy.