Which Catholic theologians say that Purgatory is a "fiery moment"? I was watching a video interview of NT Wright about life after death, in which he makes a statement that:


  Some Roman Catholic theologians now say that that's actually what Purgatory is actually about. That fiery moment when everything we've done which is not of God and which is not Kingdom Building is just going to be burned up. And they will say that's in a flash. It isn't years and years which you can quantify and get time off for good behavior or whatever. Rethinking Life After Death (NT Wright) -- 22:30


To which Catholic theologians is he referring, whom hold a view, or express the possibility, that purgatory is instantaneous/momentous, as opposed to a long "process"? Where can I read more about this concept?
The only one I've seen Wright specifically identify is Pope Benedict XVI. In Wright's 2004 book For All the Saints?, after briefly discussing Karl Rahner's unusual purgatorial theology, he turns to a discussion of Benedict:


  Perhaps more remarkable still is the view of Cardinal Joseph Ratzinger, who has held high office in the Vatican for many years. Building on 1 Corinthians 3, which we shall look at presently, he argued that he Lord himself is the fire of judgment which transforms us as he conforms us to his glorious, resurrected body. This happens, not during a long-drawn-out process, but in the actual moment of final judgment.
  
  By linking purgatory to Jesus Christ himself as the eschatological fire, Ratzinger separates the doctrine of purgatory from the idea of an intermediate state, and thus snaps the link that, in the Middle Ages, gave rise to the idea of indulgences. One of the greatest contemporary Protestant theologians, Wolfhart Pannenberg, says that in Ratzinger's view, 'The doctrine of purgatory is brought back into the Christian expectation of final judgment by the returning Christ' -- in other words, Ratzinger has brought the idea closer to a biblical model.


One example of Benedict's conception of purgatory as a "moment" can be found in his book Eschatology (pg. 230-231):


  Purgatory is not, as Tertullian thought, some kind of supra-worldly concentration camp where one is forced to undergo punishments in a more or less arbitrary fashion. Rather it is the inwardly necessary process of transformation in which a person becomes capable of Christ, capable of God and thus capable of unity with the whole communion of saints. Simply to look at people with any degree of realism at all is to grasp the necessity of such a process. It does not replace grace by works, but allows the former to achieve its full victory precisely as grace. What actually saves is the full assent of faith. But in most of us, that basic option is buried under a great deal of wood, hay and straw. Only with difficulty can it peer out from behind the latticework of an egoism we are powerless to pull down with our own hands. Man is the recipient of the divine mercy, yet this does not exonerate him from the need to be transformed. Encounter with the Lord is this transformation. It is the fire that burns away our dross and re-forms us to be vessels of eternal joy.


Another more recent example is in his encyclical Spe Salvi (paragraph 47), in which he, like Wright, mentions "some theologians" as sharing said view without specifying them:


  Some recent theologians are of the opinion that the fire which both burns and saves is Christ himself, the Judge and Saviour. The encounter with him is the decisive act of judgement. Before his gaze all falsehood melts away. This encounter with him, as it burns us, transforms and frees us, allowing us to become truly ourselves. All that we build during our lives can prove to be mere straw, pure bluster, and it collapses. Yet in the pain of this encounter, when the impurity and sickness of our lives become evident to us, there lies salvation. His gaze, the touch of his heart heals us through an undeniably painful transformation "as through fire". But it is a blessed pain, in which the holy power of his love sears through us like a flame, enabling us to become totally ourselves and thus totally of God. In this way the inter-relation between justice and grace also becomes clear: the way we live our lives is not immaterial, but our defilement does not stain us for ever if we have at least continued to reach out towards Christ, towards truth and towards love. Indeed, it has already been burned away through Christ's Passion. At the moment of judgement we experience and we absorb the overwhelming power of his love over all the evil in the world and in ourselves. The pain of love becomes our salvation and our joy. It is clear that we cannot calculate the "duration" of this transforming burning in terms of the chronological measurements of this world. The transforming "moment" of this encounter eludes earthly time-reckoning—it is the heart's time, it is the time of "passage" to communion with God in the Body of Christ.


James Akin, senior apologist at Catholic Answers, seems to endorse Benedict's view in How to Explain Purgatory to Protestants:


  So the Church has never said that purgatory involves the same kind of time as we experience here on earth, or even time at all. Thus Cardinal Joseph Ratzinger, no theological liberal, writes that purgatory may involve "existential" rather than "temporal" duration (cf. Ratzinger's book Eschatology). It may be someone one experiences, but experiences in a moment, rather than something one endures over time.