Hashirama was fighting off some Uchiha that was near the Senju territory,he didn't hate the Uchihas but he needed to protect himself some how. Though Hashirama was strong,he wasn't strong enough to beat some of them like Madara Uchiha himself. He ended up injuring himself while fighting him. Hashirama now laying down in the woods covered in his own blood and was reflecting the fight with sadness. He just wanted this whole war to stop.