A woman is tossed into water with small sharks so that people can watch her be eaten. They have a camera, and movie does linger on shots of her being bitten until she dies
He sacrifices himself, which is a different category on DTDD. It is also not directly after he learns, nor is it the reason why he does it. He's trying to avoid his friend dying as well, when he knows at least one of them is going to end up dead.