I think it shows Scotty shooting the assassin, he crashes through the glass to the floor below, and they show people gather around him. Then it cuts to the next bit of dialogue.If I remember correctly, the assassin is shown to have red blood, but since the reveal is cut, they don't call attention to it.
In the updated version, it continues from the people gathering around, Worf dipping his hand in the blood to obeserve it isn't Klingon blood, and the mask is taken off to reveal West.