The gear works, the room is set, the click is gone. Now they just have to play it.
This is the tracking session itself. Full movements, top to bottom, eighteen players with nothing to follow but each other and Peter's baton. Between passes, Fab reads the take back from the gallery movement by movement: second movement essentially perfect, first movement's entrances need another go, third movement's ending has phenomenal energy but the cut-offs in the opening bars are not tight enough, and an ensemble that is not quite together reads as uncertainty, which this piece cannot afford.
Then the strategy, which is the real lesson of the episode. Rather than picking at it, he asks for two complete takes of a movement back to back with no talking in between. Keep the players in it, do not let analysis cool the room down. Only after that do they go surgical, and only where it is actually needed: the opening up to the first viola solo, then the coda from four before D where Yvette comes back alone, then bar 75 to the end. The middle gets left completely alone, because "the middle was bananas, you don't need it." Nobody re-records something that is already right.
Running underneath it, the things you cannot fix. A city that leaks into an open room, a floor that creaks under eighteen chairs ("it's part of the joy"), and a score whose meter changes so often that finding a pickup point means counting bars out loud. It ends the way these days should. "The pocket was so good." "We did it."