Timer went off!

Potty training is going really well with the twins-as long as we use the kitchen timer.  If you ask them to go potty without the timer having gone off,  they will often refuse.  But if the timer goes off, boy, they both yell "timer went off!" and run in the bathroom, no arguments at all.  And sometimes they don't even have to hear it, if we have forgotten to set the timer, Papa will just announce that the timer went off and they will respond the same way.