is attack on titan (shingeki no kyojin) episode 42 filler?

The heads of the military meet to dismantle the Scout Regiment as the gallows are publicly erected in the city for the impending execution of Erwin Smith. In the throne room, Erwin tells the King and the assembled nobles about how the Scout Regiment serves as a spear to protect humanity.

If Wall Rose was breached, its residents would take refuge in Wall Sina again, but the earlier evacuation decimated their stockpiles. This time the residents would be forced to fight for resources and a civil war would erupt between Wall Rose and Wall Sina.