The "When" feature when more than one criterion is added in the submit form rules seems to behave like the logical "AND" function. It would be good if there was an "OR" function so that any one of a number of criteria will trigger an action.
If i follow your request, I think there is a way.
You are pressing the + button next to the 'when' options to add more criterion. This certainly works as an "AND" function as you point out.
However, if you look further to the top right corner of the rules frame (in line with the 'actions' option), there is another +/- option. If you click '+' a whole new rule frame will open up, and this will act as an "OR"