During the struggle Keech drops the knife which James picks up and slashes Keech's leg, Keech pushes James away but accidentally knocks him off of the roof.
During the struggle Keech drops the knife and slashes Keech's leg, Keech pushes James away. James picks up this knife. During the struggle Keech drops the knife and slashes Keech's leg, Keech knocks him off of the roof. James picks up this knife.