I didn't realise that the "optional" boss fight with Tyrant would actually unlock the "final fight" trigger as I believed you needed all the MO disks. This is not the case, MO disks or Tryant are all that is needed. Using this new route I was able to shave two minutes off of my previous PB. Despite the long cutscene before Tyrant for the "Barry betrays Jill" ending, I believe that choosing this ending over "Save Chris" saves a considerable amount of time because of the increased inventory space and reduced puzzle solutions required. Better execution, timing and luck with enemy encounters could easily bring this down. SOB as of this record was 17:35, but I believe it can go plenty lower.