Everything the series has been building toward. Fab opens the finished Luna session and deconstructs the mix of 3 Pieces for Strings and Guitar in front of a live audience.
The groundwork was laid in the edit: tone was found already, so this is balance. The main array against eighteen spot mics, and who wins where. Cellos and basses holding their ground under violins that were always going to bury them. A distorted electric guitar seated inside a string orchestra without carving a hole in either. Percussion placed into the same room as the strings rather than sitting on top of them. And the problem that shapes every decision, the one Fab named at the end of the edit: a piece written with orchestral dynamic range has to survive being played in a car and sitting next to everything else on streaming, without flattening the quiet passages into nothing or squashing the loud ones.
This section was never shot as a normal episode. It got far enough out of hand that it became a livestream instead, which is why you are watching it happen live rather than cut.