There is a ‘Run Once’ program feature you can use. If you need to run this frequently, you can add a new program, and set it to ‘Disabled’ so that the program won’t run normally, but when you go to ‘Run Once’ you can load it and run it immediately.
Also if this just involve one zone, you can at the home page click the zone and type in the amount of time to trigger the zone to start immediately.