The middle one wanted to come downstairs. So she used the age-old excuse that she needed to use the restroom.
It was time to come eat lunch, so I asked them to come downstairs to get their lunches, and instructed the middle one to take care of business before she began eating. She refused, saying that she didn't need to anymore. I told her I would wait until she went to give her the sandwich. She refused. I refused. It was a standoff.
I informed her that if she held it too long, that her eyes would turn yellow, and that the next time she cried that instead of tears, pee would come out. She was steadfast. The oldest one hopped up from the table and walked past, "really, mom? pee will come out your eyes?" He continued to walk past me toward the bathroom.
Apparently he'd been holding it, and he was now worried. And the middle one folded shortly thereafter, but I think that had more to do with me starting to eat her sandwich.