Invoked: Bob is doing this on purpose with the faucet in the kitchen, alternating the temperatures.
"You've been in that shower for half an hour. Get out or I'll flush the toilet."
Bob wants to take a hot shower, and the fastest way to heat the water up is to flush the toilet.
Defied: Bob decides he'll hold it until she's done (of course, if this is a Potty Emergency, he'll either use the toilet without flushing out of sheer desperation or pee somewhere else — out the window, in Alice's backyard garden, in a potted plant, in the kitchen sink, at a neighbor's house, etc).