My characters have taken the bit between their teeth again. They do that periodically. To a limited extent I don't mind. As I keep saying, a story is "something happened to someone and this is what came of it". In other words, the characters drive the story, the plot doesn't form the characters.
But sometimes I have to herd them back into the corral. Or at least back into the right pasture. If I let them wander loose I would be writing the same book when I die of old age and my kids would have to finish it. As it is I added a fourth section because it just made sense to break the narrative that way. What was intended to be a fairly brief concluding section is now headed for an in-depth undertaking.
What are you going to do? It really does belong to the characters. If I'm not willing to let them tell their story they way it actually happened, then there is no point in bothering with it. So back to the keyboard. I have an execution to describe.