Like others have said you don't need the pan at all. Adds a dimension of flavor that's good in some things. I never put water in the pan. I hate the mess it makes, and I don't need it to stabilize temperatures.
I've never cooked on a U.D.S. so I don't know if the flavors are the same as what happens on a U.D.S. but I imagine it's about the same thing.
The Life of the Knife is Ended By! The Wife.