Hello !
It's my first contribution, so I hope you enjoy it (And sorry for my english, I'm French, and I use Google translate for part of my text)
You can go out of Brawler's Guild Arena (for the Horde) with this method.
For most jump, I use Slow Fall and Blazing Speed (It is two mage spells, but with equivalent spells, it may be feasible)
Here are the steps in pictures :
https://i.imgur.com/zO6k1hP.jpg Slow Fall and Blazing Speed
https://i.imgur.com/scMkAUG.jpg Nothing
https://i.imgur.com/DgqzB6a.jpg Slow Fall and Blazing Speed
https://i.imgur.com/P3nDLbh.jpg Slow Fall
https://i.imgur.com/Djj1pxc.jpg Enjoy !
That's it !