Q: Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title
At the end of the very last episode of Breaking Bad, Walter picks up Todd's phone and answers Lydia's call. He tells her that he poisoned her with ricin. Why did he do that? Knowing that she'd been poisoned, Lydia could get medical help and survive the poisoning.
A:
Why did Walter tell Lydia what he did to her?