Unresolved guilt. I think Louis starts in a place and start ins a very different place. He probably starts with a false confidence, he thinks he understand death because he’s an ER doctor, and he’s been around it a lot. But he really doesn’t understand death. He and Amy both go through different journeys, where at the end they criss-cross. Amy ends up being someone who’s willing to accept grief, to look evil in the eyes. Whereas Louis at the end of the movie has gone completely opposite, and now he’s the one who can’t accept grief, and he’ll do whatever he can to avoid death. He’s a hypocrite, so the two end up in very different places than where they began.