Henry stopped in the tunnel because he didn't want to get wet but that wasn't the only reason. Henry knew that Sir Topham Hatt was getting tired of Henry's performance and he knew there was nothing he could do about it. Henry had lost hope in being a useful engine. So the rain was probably the last straw for him and so he decided to park it in the tunnel. Henry probably knew that Hatt was going to scrap him, at worst. So he didn't have much to lose. Henry probably didn't realize that he would stay put there and have to watch engines fly by for what could have been eternity. But even if he had stayed there permanently, that could have been a better situation than being scrapped. I just kind of had that thought after watching The Unlucky Tug's video about Henry last night. Let me know what you think.