When I worked out the basic plot for “Entanglements of Honor: A Pride and Prejudice Variation,” I wanted to go with a variation of the standard compromise situation. Rather than having Darcy compromise Elizabeth, I wanted Darcy to compromise Jane, and Bingley to compromise Elizabeth. Then I would have them switch.
The problem was finding a single event that would cause this. I didn’t want one couple in a snowstorm in a cottage and the other couple accidentally locked in a room. I came up with Miss Bingley arranging for a large fire to be lit in an unoccupied room, when she was unaware the damper was closed. This gave people reason to believe there was a fire when there wasn’t. (Well, actually, there was a fire, but it was safely in the fireplace.) It also had the advantage of making Miss Bingley unhappy, because she caused two marriages to take place that she definitely did not want to happen.
I enjoy making Miss Bingley unhappy.