Think about it, we're yet to see the AK actually interact with anyone other than Bruce, and in the footage shown so far it doesn't exactly look like the soldiers are noticing the Knight walking amongst them. Could it simply be that the Arkham Knight is a figment of Bruce's imagination - a realisation of his own psyche, twisted from the time he spent in the Asylum in the first game, not to mention losing his 'other half' when The Joker killed himself in City? Doubtful, very doubtful - it'd be a bit strange doing a 'he's lost his way'-style narrative after setting up a version of Batman that's so steadfast in the other instalments, but Dark Knight Rises' version of the character took a massive backwards step on the big screen, so it's entirely possible the Arkham Knight portion of the game is only a first half-climax type deal.
