You can climb onto any "broken" wall in Drak'Tharon Keep. Here is an example of one that lets you get out of the map without dieing, the majority you can get out, but you die from fall damage.
It's easy to find, after you do the Dinosaur boss, and run up the stairs, it's on your left. The catapaults are pretty noticeable.
Step 1:
Run at the wall at an angle, and do your best to land on it;
Step 2:
While standing on the broken bit of the wall, aim yourself at a 90° angle to it, and Run + Jump;
(Best from the broken bit of the wall circled above)
You'll fall through the ground, and alot of stuff, then land in the water. You can then swim to shore, mount up and see a huge area without mobs or NPCs.
Running too far will take you to untextured map, and eventually "nothing" where you just sorta float on the spot.
Have fun! :O