One of the things I used to wonder about when I read C. S. Lewis’s The Last Battle was that literal died-in-a-train-wreck ending . . . it always seemed to me like a rabbit pulled out of a hat. Then one day while idly mousing around the internet, I found out about the 1952 Harrow and Wealdstone railway crash, a three-train collision where 112 people died and 340 were injured, and I thought, “Yeah . . . for a book published in 1956, something on that scale that happened in 1952 would have still been taking up space in the author’s mind during the writing process.”
Writers aren’t necessarily in control of what sinks into their memories, and they don’t always have a say in how it may bubble back up to the surface later.