Hmh? That explains nothing. Kirk throws himself into a fight with the Klingons despite spotting them well in advance, suggesting he has no fears about the outcome (and the Klingons share his opinion, considering their own position hopeless). Yet when the battle is joined, the Enterprise loses, and Scotty apologizes. Thus, it seems pretty clear that Kirk had no idea that he was the real underdog there, and Scotty kept his possible doubts to himself.
Kirk also wonders about either the Grissom or her crew firing at him or his ship. We don't know what he would do if this happened, nor what he would do if the potential adversaries joined forces with him - all we know is that Kirk is sufficiently worried to speak out aloud. Worried of hurting the Grissomites? Worried of failing in his quest because of the Grissom? Worried of dying? We don't see him preparing for battle, suggesting he doesn't think highly of the Grissom armaments. But he doesn't broadcast a message dictating his terms or asking for parley, either.
If anything, Kirk was more aware of the Klingon threat and should have negotiated with them when he had the clear upper hand ("You're where you shouldn't be, a dozen starships are on my heels (for reasons you don't need to know), and I can seeeee youuuuu. Now eject your warp core orI'll eject it for you."). The Klingons would be frightened out of their silly vests by Kirk so callously giving up his tactical advantage and thus demonstrating he doesn't even need to resort to such...
