When you go into the Oval office and get the intermission sequence with Parchezzi where he detonates a bomb and runs off, you usually have to chase him through the building for a final showdown on the roof. However, you can easily take him out in the office and not have to chase him down. Bring your Silverballers with dual action and fully automatic attachments, then pull them out before you enter while making sure they are fully loaded. As soon as the intermission sequence starts, hold the trigger and do not release. When he is done with this speech, the bomb detonates and, while you are unable to take any movement action, your guns will still fire a decent full auto spray in that split second before the disorientation effect hits you, killing Parchezzi before he can run off.