Doesn't the rule exist merely for those wishing to remain in the circuit and to prevent a circuit in the opposite direction (ok - unlikely, but this is the law after all) or on the wrong side? If you are leaving the circuit there is no sensible need to continue to conform to the pattern of traffic, or you will stay in there forever, or rather until a full stop landing at the same aerodrome. As long as you make all the turns you need to, prior to departing the circuit, in the correct direction, and you are sufficiently situationally aware by listening out, and visual anyway to provide your own separation, I think you have satisfied the rule. Having made your safe right turn out in the above example I would argue you are no longer ruled by the "vicinity of the airport" part, as it is clearly your intention to depart the vicinity and very shortly later you have done so anyway.
I don't think Wirlygig even needs to ignore the rule, I think he is conforming to it until he choses to safely depart the vicinity.