Hey, long time no post. Just found this out thought it may be of some use to you. This exploit allows a Warlock to teleport out of the Dalaran underbelly during a duel to above dalaran without igniting the flee timer, this is useful for warlocks who can apply DOTs pressure and then escape, if the other person wishes to follow they must ignite the flee timer.
This is only for warlocks, and requires small preparation.
The simplest place to do this is the center fountain in dalaran as it is above the center dueling stage in the sewers. Place your summoning circle and go start the duel. You now have 6 minutes and as long as you are on the center duelling circle or close you can now summon to your circle and be above the underbelly by the fountain without incurring the flee timer. Even if your dots don't kill the player ether one of you must forfeit by walking out of the duelling radius (which appears to have no z axis restriction).
I realise this doesn't have much use other than to confuse duellers and just to have some fun with, but it could be useful if expanded upon.
I apologise if this has been posted before. Enjoy and tried and tested.