I'm fairly certain that GMs often consider many more moves than what they verbalise. If you look at Naroditsky's speedrun episodes, there are many moments where he verbalised a few of the opponents responses, and sometimes said opponent plays something else and he goes "I looked at that, but thought that wouldn't work" (or something along those lines). I've also seen these sorts of things in clips from Levy who is a "mere" IM.