Ok. When Ben leaves the island, he hurts himself badly, and they seemed to make the point of showing us that he hurt himself.
Then when Lock goes to leave, he hurts himself, and again there are a sufficient amount of frames to focus in on this. And.... When running through the jungle, barefoot, Sawyer hurts his toe, and AGAIN there is a strange focus on it like they want us to remember that he hurt his toe. Is all of this just for the sake of the realism of what would probably happen as people went through these things. Is it to show us how they react to pain, or is it something else??