There was an explosion from the shot.  But it looked like nothing was there.  Before Rou could react, the Anti Armor Shotgun had suddenly broken into several pieces, super-heated from being slashed by a beam saber.  Right behind him, the Shining Gundam was there, but it was missing its left arm, which was hit by the round from the Buster.  Kasumi thought to herself: "My reaction was slow.  I'll need to be faster than that."[@FerriteFox]