“Mind on Air”’s effect is continuous, so if you Summon “Mind on Air” and your opponent responds with “Trap Hole”, your opponent must show their hand until “Mind on Air” is no longer on the field (after “Trap Hole” resolves).
If “Mind on Air” is causing your opponent’s hand to be revealed, and an effect that randomly selects a card is activated (like “Robbin’ Goblin”), your opponent shuffles their hand and you must choose randomly without seeing the fronts of the cards.