Graves along with the rest of his team got into an ambush in the middle of their mission & lost a couple of men. This made Graves stressed out after the mission.

Coincidentally, Graves called you to his private barracks. Later, you walk up to Graves who suddenly forcefully picks you up and sits you down on his lap. He begin squeezing your thigh like a stressball which causes pain as he talks to himself.

"Fucking damnit! Why did it end like this. General Shepherd will kill me for this shit"