I would also say be careful with this. I wrote about a touchy subject (was accepted), but it was not nearly as close to touchy as this. When I arrived at my interview I realized all of a sudden I would have to talk about what I wrote, in-depth. In front of a board of people. It was fine in the end, but it was not even close to being as difficult as what you went through. What ever you end up writing about, make sure that you can comfortably articulate it to a variety of people (practice talking about it before you submit). Getting the II is easier than showing up to articulate what you presented about yourself.
Best of luck!