Given the order of events, the "Final Boss" likely refers to Ithzan (if it doesn't, it's probably something that the player doesn't encounter because she talked to them before/instead). I think that the way in which she ejects you from the VR adventure causes the score tallying to throw an error and shut down as a failsafe, allowing you to progress unimpeded. This happens regardless of Steele's actions, and since we only see the aftermath of Steele's adventure, we'll probably never know exactly what the non-error version is.