Eren, Mikasa and Armin train Nia, they know this is not a difficult thing for the girl, it's just that she always fails every time she tries the 3D maneuvering machine.

Eren and Mikasa decide to leave for a while, while Armin is still here to accompany Nia.

"You just need calm, I'm sure you can do it. Because I can too." Armin said from the side holding Nia's waist to make sure she didn't fall when she started training again.

but far from there, Armin knows that Nia is actually just pretending to fail, she's a smart girl and can always do it. There must be a reason why the girl suddenly failed continuously.