Today i finally had to deal with the quest to get to use pvp vendors in Orgrimmar.
To start the Event, i had to go in through the “back” entrance, the place you fly in/out of UC through.
I went down to the room Sylvanas usually stays and Thrall was riding around in circles. I could interact with him and start the event.
He despawned shortly after the event started and he appeared in the courtyard and the event worked as expected.
In the Royal Quarters we had to kill varimathras twice. First time thrall ran away just before we could fight him, though came back shortly after we defeated varimathras the first time.
After all of this, Wrynn appeared, flexed on us and we could hand in the quest