Reprise
Disclaimer: I own nothing of importance, and I'd say Castle is quite important.
Fifth Iteration:
By now, he had begun to lay out the rules of the game. At first he was far too shocked to believe it wasn't a dream, but starting to blubber and cry right after being held as a human shield apparently caused you to get sent in for a bit of therapy, especially when you're ranting about things that are obviously impossible. That broke the rules.
On the second trip he lasted for a case before he started screaming in the middle of the station. Esposito tackled him before he fired but after he had taken Ryan's gun and waved it in the air. That broke the rules.
Third time through he doesn't even resist while Harrison has a gun on him. That broke the rules.
This time though, things will be different. After Harrison was arrested, he had gone into his office and sat alone for 24 hours, typing. He made lists of everything he knew, everything he guessed at, and everything that was lucky chance the first time around. He noticed that the last two lists were a lot longer than the first.
He makes little changes at first. First he manages to keep Max alive by wondering why the kids didn't just pay the dealer off 24 hours earlier. Then he "notices" the elevator timing earlier on, preventing the hostage situation. Finally, he wonders if finances had anything to do with Horn's murder, leading to a quick inquiry into Laurie Horn's monetary situation and her early arrest. The hard earned knowledge from before gives him an advantage in every crime they encounter, and he intends to use that information to slowly begin to close the noose around Coonan and the others responsible while also hopefully saving lives by speeding up the closure of cases. Richard Castle feels good about his chances now that he has a plan.
Kate Beckett dies from a GSW inflicted by Frank Nesbit while attempting to place him under arrest.