So did a search on "Sunwell" and didnt find anything related so here it is.
All you have to do is kill kael while he is finishing casting Gravity lapse and viola
[ame="http://www.youtube.com/watch?v=hd6zLyWhBS8"]YouTube- Kael'Thas Flying Bug[/ame]
All credit goes to :SaltShaman Of Youtube: Great explorer and awesome videos