Jean had just finished yelling at Armin about how useless he was not knowing Armin was probably the only reason the survey corps were able to regain the wall Maria. Armin was the brains, the one who made the plans for everything and he himself had killed a good bunch of titans but he never gets any credit. Armin stood there listening to Jean yell at him and there was a certain phrase that caught him off guard.

Jean: you do nothing! Your good as dead! If it weren't for you the other scouts wouldn't have died!

Armin stares at him, tears starting to form in his eyes, he runs out of the mess hall, the other scouts watching and including sasha, Connie,mikasa, eren and levi saw what he said.Eren was extremely overprotective of Armin so this was not going to end good.