is attack on titan (shingeki no kyojin) episode 44 filler?

Rod Reiss returns with a satchel in hand. He is relieved that there is finally no one here but him, Historia Reiss, and Eren Jaeger.

Rod tells his daughter that her sister, Frieda Reiss, is not entirely dead and that her memories live on, and asks if she would like to meet her. When she agrees, he kneels and takes a syringe out of his satchel.

Eren recognizes it as the kind his father used on him. Elsewhere in the Underground Chapel, the Anti-Personnel Control Squad hunkers down and prepares for an attack.