5. Scarecrow
An extrapolation from the whole 'It's inside his mind' idea was that the AK was a manifestation of Scarecrow's Fear toxin, an embodiment of Bruce's justice system bringing the fight to him for failing to save Joker. A solid premise - save for the fact that the world isn't melting or falling apart like it usually is in Scarecrow's induced visions - but one that's instantly torn down when the new footage shows him both walking alongside the Knight, and appearing across the many screens in Gotham. That's not to mention it would be the straight-up dumbest thing possible if Scarecrow and the Knight were the same person, making it highly unlikely, not to mention Rocksteady deliberately chose their own writing team outside of standard DC-scribes for this one precisely to conjure up something spectacular.