Use goblin glider from the catapult, or rocket boots from the pillar and jump to the lamp post.
From the lamp you jump to the tiny cogwheel, then to the big one. From here you jump to the log using any speed increase or rocket boots. Then just follow the pictures and you get outside the arena into a desolate orgrimmar. Elevators are still working, and you can use these to explore the mountains. I let you explore the rest by yourself, but it is possible to reach the high peaks and goblin glide back into the arena area.
Have fun