You're right. He fixed the leak. Worf "made things the way they were SUPPOSED to be". He blatantly understood, in a dumbed down way, what Guinan understood in "Yesterday's Enterprise", that there is a certain way that this certain timeline is supposed to be, and it needed to be repaired to, in his case, stop him from shifting between all of them, or in Guinan's case, prevent a reality where the Federation and Klingons were in a continual war. I present to you a reality where the Federation is dead. What would you do?