on a monster surge... monsters go to the outskirts because the arkham limit is reached. i get that, but when the outskirts limit is reached and then exceeded the timing of events is not explained.
so...
do you draw all of the surging monsters at once and then put them in the outskirts, filling it and then returning them from the outskirts to the cup after the limit is exceeded. (doing this may mean that you empty the cup during a surge and thus awaken the AO)
or ... do you draw and place them one at a time and so the monsters may return to the cup from the full outskirts before all of the syrge monsters are drawn from the cup. (in this version you may draw monsters that have just been returned to the cup, and its not likley that the ancient one will wake during a surge using this method).
consider this example
the monster limit in arkham is full. the outskirts limit is (say) 4 with two monsters already in it, and 6 gates are open. Oops! there is a real nasty monster surge, 6 gates that means 6 monsters are going to surge... what do you do?