Jesus appears to think that his return will be comparatively sudden:
36 “But concerning that day and hour no one knows, not even the angels of heaven, nor the Son, but the Father only. 37 For as were the days of Noah, so will be the coming of the Son of Man. 38 For as in those days before the flood they were eating and drinking, marrying and giving in marriage, until the day when Noah entered the ark, 39 and they were unaware until the flood came and swept them all away, so will be the coming of the Son of Man. 40 Then two men will be in the field; one will be taken and one left. 41 Two women will be grinding at the mill; one will be taken and one left. 42 Therefore, stay awake, for you do not know on what day your Lord is coming. 43 But know this, that if the master of the house had known in what part of the night the thief was coming, he would have stayed awake and would not have let his house be broken into. 44 Therefore you also must be ready, for the Son of Man is coming at an hour you do not expect. (Matthew 24)
So what does this mean for those in Purgatory? Can Jesus actually let people out before they have made compensations for the temporal consequences of their sin? Will it be like the men in the field? One believer is released from Purgatory but another stays? Or does everyone get out because the return of Christ cancels all penalties for sin?
But if Christ’s return has the power to overturn the claims of Purgatory, imagine what the crucifixion and resurrection might do to both the temporal and spiritual consequences of sin.