I've been toying with the idea of simply continuing chapter 12. I'll need to have an extra line break to signify the slight jump forward by a day, but it will probably flow nicer if I do continue following that particular POV character.
Not all is lost, however. Chapter 13 is not being deleted. The act that takes place in this scene is still important. The problem with it is it's in the wrong book. This scene will be revived for book 2 of the series (though it will need a bit of a rewrite to fit into the timeframe of the second book).
So, I realized I was being a bit hasty, or at least semi-hasty. Most of Chapter 13 can stay put. It is the aftermath of the event that takes place that is being removed for use in book 2. I simply need to provide the proper reaction that this story needs to continue moving forward.
Now that I've got that settled...