Neville, I wasn’t so clear in my last comment. I meant that Rashi or any mefoiresh on the Chumash is meant as explanation to the pesukim in the Chumash-they do not contradict the Chumash. If they appear to contradict a pesuk in the Chumash you are interpreting the mefoiresh wrong.
When you are having a discussion on Gemorah then a pusok from the Chumash will not come into the discussion. When you are talking about a pesuk in the Torah, you can bring a mefoiresh to explain it, not to contradict what the Chumash is saying.
You are taking the Word of Hashem very lightly. Everything that the Rabbis expound upon is taken FROM the Chumash, not vice versa.