At last, we're solidly in Act 3.
We've suddenly gone from not much happening at all, to a lot happening all at once. Out of all the new topics introduced, there are two big ones: Eraqus and the X-Blade. We'll table the X-Blade talk for now. Instead, I want to focus on Eraqus and his questionable decision making.
The game wants to portray him as an ultimately well-meaning man that has become so blinded by his obsession with the light that his judgement has been clouded. To some degree, this works, particularly in his interacts with Terra. These moments, and the way Terra remembers him, give off the impression of an "All Darkness Must Die"-type Knight Templar figure. While he loves Terra like a son, it's obvious that he doesn't approve of Terra's proximity to the Darkness.
That said, I also believe that Birth By Sleep wants me to think of Eraqus as an intelligence (not omniscient, we have Xehanort and Aqua for that) person in all other respects. If that is the case, he fails miserably. We harped on it a lot during this episode, but I just cannot get over how Eraqus let Xehanort watch the Mark of Mastery exams despite knowing he tried to start the Great War of Kingdom Hearts (For Science!). And on top of that, he neglected to tell his students about this event.
This could be forgiven, but there really is no compelling reason (at least, the game doesn't offer one) for him to make these mistakes. There would be no plot to Kingdom Hearts: Birth By Sleep if not for all the secrecy. Considering how much (and we haven't even gotten started on most of it) of these events tie directly into Kingdom Hearts 1 and 2, Eraqus and our 3 "heroes" just come of this looking completely irresponsible.