The story is:
I was running Drak'Tharon Keep with a few pals when we were just about at the last boss. We were past the raptor boss, up the first set of stairs, past the mobs of fighting I ran to the very top of the staircase, faced where I had just came from, popped my rocket boots, jumped forward at high speeds, popped my parachute cloak and flew over the ledge that held me from the outside of Zul'Drak (you can't jump over the ledge normally).
So there I was, standing in mid air, floating above Zul'Drak, behind me was Drak'Tharon Keep, which I had just hopped out of, to the right of me was the enterance to Drak'Tharon Keep and to the left was the area that had the raptor boss in it, where I had came from.
I waited for my parachute cloak to cooldown incase I fell through the ground (mid air which I was standing on like it was ground). I ran far far to the right, as far as I could on this invisible ground I was standing on and of course, I fell through, down to the floor of Zul'Drak, but still instanced in to Drak'Tharon Keep. At this point I popped my parachute cloak in fear of dying.
I landed safely on the floor of Zul'Drak. Now all I had to do was explore. I wont tell you where it is, or how to get there, because the fun of exploring is to explore, but if you use my strategy to get out of Zul'Drak, by simply mounting up and running around, eventually you'll stumble upon some ground textures that look familliar. It's not hard to find.
I know they say a picture is worth a thousand words, but so is a thousand words. I will post pictures later but for now it's late and I am lazy. Try your best to follow that little story guide, you must be an engineer though I'm afraid, and a stealthy.