Rashi (6:18) writes that Hashem made a special covenant with Noach to ensure that the animal fodder on the ark did not spoil and to ensure that Noach came to no harm from the wicked people around him. The Brisker Rav notes that no special protection from the wild animals aboard the ark was afforded to Noach – indeed, the Midrash tells us that a lion took a nip at Noach when he delayed his food. The implication is that Noach had more to fear from the wild people around him than from the wild animals he faced in the ark.
I would like to suggest a different way to make sense of the diyuk that avoids the Brisker Rav’s conclusion. In Parshas VaYeishev we read that instead of killing Yosef outright, the brothers decided to drop him into a pit. The Torah writes that the pit was empty of water, from which Chazal deduce that it was filled with other things – snakes and scorpions. Why was lowering Yosef into a snake filled pit better than killing him directly? The Ohr haChaim (which we discussed here) famously explains that snakes and scorpions have no free will – their behavior is mechanistic, controlled by Hashem alone. If Yosef was truly innocent and deserved Hashem’s grace, the snakes and scorpions would not harm him. If he was guilty, he would die. There could be no surer test of Yosef’s standing in G-d’s eyes. Ahuman being, however, has free choice that Hashem does not interfere with. The fact that the brothers or anyone else might be able to harm Yosef would not establish his guilt or innocence.
Based on this I think it makes perfect sense for Noach to need special protection from the people who surrounded him but not from the wild animals. The lions, tigers, and bears would only harm Noach if Hashem allowed; wild people have no such constraints on what they could do and the damage they could cause.
My son argued that if anything, Rashi proves the exact opposite of the case I am trying to make. If humans have free choice, how could Hashem promise to protect Noach? My counter-argument is that the pasuk is speaking of a bris, a special covenant that goes above and beyond the normal bounds of hashgacha. Even the Ohr haChaim would admit that Hashem has the power to interfere with free will. Hashem normally does not do so because the relative cost of abrogating such a fundamental principle overrides any benefit gained by doing so. However, in exceptional circumstances, all bets are off.
Two final notes: 1) I have heard that the Brisker Rav did not hold like this Ohr haChaim; 2) If someone has time it would pay to dig around and see if there are other Rashi’s that either agree or disagree with the Ohr haChaim.