Hello; The Citation was cleared to take-off before the 747. Good reasons for this. 1: A small can get in the air whole lot faster than a 747. 2: A 747 produces tones more thrust than a Citation on and after takeoff. This can be trouble for smaller planes. Its called "wake turbulence". This was probably a good move to save time by the ATC. The wake turbulence of the Cessna won't affect the huge 747 at all but if the 747 departed before the Cessna, the Cessna would have had to wait for a long time as the wake turbulence from the 747 would literally blow the Cessna away. This in turn would require a longer hold time for the Cessna, occupying the runway and holding other jets behind it as well. An EL AL Boeing 747-400 Freighter made a 180° turn on runway 22L at Liege Airport and just after he finished the turnaround a small Cessna Citation Jet took a shortcut and entered the runway right in front of the Boeing 747. The heavy Boeing had to wait until the belgian citation jet departed.