I read that as starting a conflict within a greater, unresolved conflict.  Harry is still in personal danger, and now his friends and allies are as well.  Starting a new conflict shouldn't in itself grant stress clearance.

The rules discussion of 'Concessions' includes the following:

A concession has to pass muster with the group before it is accepted—the conditions of the loss still have to represent a clear and decisive disadvantage for your character. If the group (note that your opponent is part of the group for this!) feels like your character is getting off easy, you’ll need to rework the concession until it’s acceptable.

Escaping a duel-to-the-death would obviously incur some serious social penalties - such as becoming an exile that would be slain on sight.  But a 'concession' that involves putting your opponents in massively-increased danger?  The superghoul intervention would have killed off the entities that escaping the duel would incur penalties with.  Sure, it would probably mean a major debt with Cowl, but it in no way constitutes a 'win' for Team Dresden, even if those players accepted it on the terms of some of their enemies being guaranteed to die as a result.

I can't imagine the people I game with being willing to propose such a concession, much less accepting it.

The rulebook says stress is wiped at the end of a conflict -- you're confusing conflict in the general sense with the conflict in the game's specific sense. According to the game's rules, a conflict is a battle. The first conflict in that scene was Ramirez and Dresden vs. Madrigal and Vitto. They kill Madrigal, and Vitto calls in the ghouls. That's the end of that conflict

  No, it's a continuation of the same conflict with different weapons.  Same battle, higher stakes.

There is no discontinuity in physical location - the entire encounter takes place in the cavern chamber.
There is no discontinuity in temporality - the entire encounter is continuous, without pauses, breaks, or interruptions, and the entities involved have to stay on their toes the entire time.
There is no discontinuity in the fundamental nature of the dangers and threats - I'd be willing to let a fistfight that turns into a car chase with gunfire count as two separate conflicts because the nature of the threats, and therefore the abstract 'stress', is so different between the two.  But that's not what we have here.

And, of course, the conflict that was initiated was a duel to the death between two Wardens and two WCVs.  The stakes are raised, but the basic conflict does not end until both vampires are dead - which does not occur until the caverns are blown.

If there were a single real example of a break, I'd let it suffice for a rest.  Say, something along the lines of that scene from The Phantom Menace where rotating force walls temporarily keep the combatants apart, and the bad guy paces while the good guy gets some meditation in.  That would count.  There was absolutely nothing like that.  Everyone is constantly in danger until they escape the killing field.

Which is precisely why Harry does that kiss with Lara to generate the force bubble that saves them both.  He was on his very last legs at the very end of the battle and needed something, anything, that he could feed into the spell to power it.  If he'd somehow cleared all his stress, mental and physical, he'd have been fresh as a daisy and wouldn't have needed to interact with a soul-sucking succubus to survive.

Please show me where in the rulebook it says that the GM absolutely cannot clear stress tracks until there has been a specific amount of time of actual, in-game rest for everyone involved.

I've never suggested a 'specific' amount of time.  But it has to make thematic sense.  Within a single 'episode' or 'session' there can be long breaks where the story as told and the time within the story don't have to match.  And within a single encounter, there can be breaks or rests that would permit stress to be cleared - if it actually makes sense that the characters would recuperate a bit in those circumstances.

Those sorts of circumstances would be uncommon in conflicts.  And most of the conflicts within the novels do not have such pauses - which makes them more realistic and believable.  I am not going to arbitrarily declare intermissions within extended conflicts if it doesn't make sense, no matter how much I might like stress to be purged.

I'm suggesting that the players get a scene break that clears refresh when they have an appropriate break in the fight -- going to a new set of opponents, new set of circumstances, whatever.

That's better than suggesting they should get one when there's a chapter break... but not by much.

Sure they do. As has been pointed out, a lot of the "dramatic" flourishes are represented by flavor, not mechanics.

  A combat doesn't need 'flourishes' to be dramatic.  The spells used in the White Night battle were described as having effects that are mechanically represented in the DFRPG rules.  A force attack that topples a crowd of enemies isn't a dramatic flourish.  A shielding that repels an attack isn't a dramatic flourish.

The guidelines for what uses of magic shouldn't count as a spell are really quite clear... and they emphasize that if magical effects that aren't spells in a mechanical sense change important aspects of the scenario that expenditure of a Fate Point might be necessary to effectively 'declare' a changed aspect.

Also, the GM has the right and ability to declare a stress-clearing pause whenever he or she wants.

  It's a game of make-believe, we can technically do whatever we want, whenever we want to.  That does not excuse problems with the rules we use to give structure and meaning to our make-believe.

Most major battle scenes are not going to permit characters to rest and catch their breath and 'compose themselves'.  In the exceptions, the characters ought to have taken cover or be protected by others.  This principle already operates with FPs and sessions - characters don't regain refresh if a particular scene ends up stretching across sessions if the GM decides it's like a two-part TV episode.  This situation is a great deal like that - if there's no pause in the action for a character, they don't get to clear their stress!

Do you really think my players - or most people playing the game - aren't going to have serious issues with the GM if the people and monsters they're challenging suddenly revitalize and lose all their stress mid-combat, just because the GM decided to arbitrarily declare a rest break?  It's not good storytelling and it's not good game play.

A refresh being declared during a break in active hostilities?  Like the time between Harry defeating Arianna and mass combat breaking out in Changes?  That makes total sense.  But not every battle is going to be like that.  The rules as they exist now don't permit that.

Rather than post a link to my most recent rambling, I'll depart from tradition and repeat myself: JB wasn't writing the books with a game in mind;

This is a perfectly true point.  It is also COMPLETELY IRRELEVANT as an argument in this context.  The issue is not whether any game can perfectly emulate whatever Jim Butcher has written or may eventually write.

Since it seems that this needs to be explicitly laid out, the issues here are as follows:

1)  The DFRPG rules do not permit certain kinds of dramatic scenes; specifically, extended combats with frequent use of magic, or any situation in which many spells are used in a short period of time.
2)  This is undesirable for anyone who might want to use this system for a game in which such scenes are possible.
3)  This also means that the rules don't properly represent one aspect of the flavor of their source material.
4)  The relative de-emphasis on rigid mechanics in FATE generally, and this game in specifically, does not excuse poor mechanics where they do exist.
5)  Trying to force the source material to conform to the limitations of this game's mechanics is inappropriate.

Not calling them a liar or an idiot.

  If we don't call spades spades, then we'll slowly be inundated with liars and idiots, won't we?

The fight with Vitto and Madrigal and the fight with the ghouls are two distinct scenes. There's a chapter break and everything.

  There's no 'chapter break' in the action, no period where Harry can compose himself.  It's all one long conflict.  The fact that it occurs across chapters is totally irrelevant - the break doesn't exist within the story, it's an artifact of the story being written out in novel form with a particular structure.  The spells Harry casts before the battle aren't part of the analysis, because there's a period of speechmaking and talking that would obviously provide a chance to catch one's mental and physical breath.  No such period occurs within the battle.

Just a little while ago we had people discussing a proposed rule that would let people clear their stress tracks in the middle of a conflict, and it was rejected with the reasoning that only one published ability permits that, and it's the Blood Drinker feature  A Taste of Death - which requires completely draining a human being.  It also banishes a mild consequence, admittedly.

Arbitrarily declaring that there are sustained pauses in the middle of a massive battle is worse than that proposed rule.

The game is not a hard-nosed, exacting simulation of every detail of the series. It is a game, meant to reflect the feel of the books as close as possible while being playable and fair.

The rules do not permit us to enact the most dramatic sections of the stories!  These are not minor trivial details.  By these rules, Harry Dresden would have taken himself out with stress and lost the major conflicts in each novel.  How does that reflect the feel of the books?

For that matter, what's supposed to be playable and fair about limiting players to so few spells?  I don't see much interesting about rendering your character unconscious, or worse, because you cast a minor spell multiple times.  It's not a part of the stories at all.

The can easily be uses of his enchanted items, which would cut down on the stress.

  Nope.  I didn't even mention the cases where his duster repelled something - those are the actual spells that he cast.

Then I think there's at least one major break during the fight, which could have wiped the stress tracks.

  Wrong.  There is a section of description in which Harry describes some of the many things happening all at once.  There is no point in the battle where Harry can pause and collect himself, free from risk and the threat of having to respond at a moment's notice to lethal danger.

Opening the rift might actually be a plot device. It's been talked about beforehand, bargained with Marcone, etc. Opening the rift might just be the action to activate this, but it doesn't have to be a spell from a mechanical standpoint.

  Other than it being a spell, which he cast.  Marcone had no ability to open a rift, nor did anyone else who came through.

The same actually goes for the final shield. I'd say both Lara and Harry took a consequence to power that, and that might have just been it. Or maybe it was just part of the cutscene after the fight was over.

  It's not included in the analysis - as I explicitly stated.

That's my main point, really. Not everything that looks like a spell actually is a spell.

  You are either a liar or you don't have the slightest idea what you're talking about.

This sort of name calling is a violation of forum precepts.  Please review the Rules. http://www.jimbutcheronline.com/bb/index.php/topic,23096.msg988906.html#msg988906  Edit your posts, and be civil on the Boards, just the same as you might if you were sitting in Jim or Iago's living room.   ~Blaze, Moderator.

The rules as published do not permit scenes such as the ones that occur in the novels covered by the game.  At most, they might be able to represent how magic works in the very earliest books.  They are incapable of emulating the performance of wizards - not just Harry, but wizards generally.  This is not something which can be handwaved away, it is a serious failure of the existing rules.