Get a bow or some decent spells. Make sure you have at least 30 in 
Acrobatics. Immediately after the
gate drops, run to your right, to where the right gate meets the fence. Jump 
onto the stone piece that juts
out, then jump again to get on top of the little piece sticking out above 
it. Once on top, turn and fire on
your helpless victims. When you have to fight mages or archers, stay on the 
ground and strafe behind
the four central pillars for easy kills.