Some grains get stuck in his cleat, and Wolverine's heart grows calm. Wolverine had been screaming and yelling and stomping around, but when the grains entered his cleat he realized where he was. He was finally able to calm down.
Now that Wolverine is calm, tears come to his eyes. Being calm has given him perspective on what his anger has done. Oh, wait no. There are just some onions (おん) in his cleats too, and they're making calm tears trickle down his eyes.