is attack on titan (shingeki no kyojin) episode 23 filler?

Annie has a dream of being trained by her father before waking up in her room. In the Stohess District of Wall Sina, the Military Police are ordered to escort the Scout Regiment convoy once they enter the capital.

The superiors put all the work on the cadets. The Military Police are shown to be lazy and corrupt which one of Annie's colleagues, Hitch, reveals she joined the police for that reason.

Another colleague, Marlo, is disgusted, revealing he joined the police so he could reform it to become a better organization which Annie respects since he reminds her of Eren.