Declan can't duck out of the hit entirely and his head rings when a fist slams into him. While Kylo goes for his head, Declan punches hard at his ribs. He can't stop Kylo's momentum, either; regardless of where or if the blow lands, they run into each other and Declan loses his balance. The most he can do is twist them away from Ronan so that when they hit the ground, it isn't on top of his brother.

He kicks hard and immediately tries to get back to his feet.