It's the McEvil laugh. If you do it just right, Dr. Evil laughs a few seconds before McCain but the music crescendos at all the right moments in the McCain clip and you can appreciate the theatrics of pure evil as they simultaneously plot to destroy the world. Watch the laughter fizzle in synchronicity at the end, too.
To watch: cue the John McCain clip up to about 22 seconds and let it play. Get ready to start the Dr. Evil clip by clicking it so it can load, pausing it and backing it up to 0.0 seconds. Click "play" on the Dr. Evil clip when the McCain clip hits 33.8 seconds (just before 34 seconds). Important: the Dr. Evil clip must start at 33.8 seconds or barely 34 seconds for the full comedic effect, so if it needs to load, you may have to try again. (Scroll Down)