User blog comment:B214/Question and Answers 6/@comment-3285616-20161121005601/@comment-9595671-20161121214734

That I don't think will show, they adapt two volumes at a time. So that event won't show because it's in Volume 11, and a 4th season will adapt Volume 9 and 10.

In other words, unless we get a movie showcasing that part of the series or a 5th season, it's probably not gonna be put in animated form. A LN anime rarely gets a 4th season, and I don't think I've ever heard of one getting a 5th.