Generally, one would structure programs like these using parallel loops, one for the Event Structure (so it will always "be responsive"), the other for whatever else you are doing. There are various ways to get information from one loop into the other -- you need to be a little careful, as you can get into a "race condition" where both loops are trying to change the same thing at more-or-less the same time.
If your loop-to-be-controlled is written so that it has an (internal) control that governs whether it is in Automatic or Manual mode, you can simply build an Event case that looks at a (separate) control, say a switch that has a Manual and Automatic setting, monitoring a Value Change for this switch. In the Event loop, you can (safely) use a Local Variable to change the Manual/Automatic control to the appropriate state.
