is attack on titan (shingeki no kyojin) episode 8 filler?

Armin wishes to be left behind to die and allow Mikasa and Conny to live. However, the two brush off his pleas and prepare to make a run for the supply headquarters.

Armin knows they will not get past all the Titans and looks back at the mysterious Titan currently looking for more Titans to kill. He stops and suggests that Mikasa and Conny kill Titans close to the rogue one in order to lead it to the heavier concentration of Titans currently assaulting HQ so that it will lessen their numbers and give the troops a chance to resupply.