"Look how his expression changes... Molly said he was going to have to feel the pain, but he was hoping he could still get away with it, so he asks the person who is most like him if there is an secret to not feeling. Unfortunately, Moriarty doesn't tell him what he wants to hear. Moriarty is numb. Sherlock is avoiding. Sherlock now realizes there is no way out of feeling pain, which scares him because he doesn't know how to do it. Which is probably why he almost just lets himself die,"