Is there any quest required to open the doors behind Palimuth?

Question

The NPC Palimuth gives missions related to the In Service of Yalahar Quest. There are two doors behind him that I am able to pass through. I was wondering if anyone can access these doors or which mission you have to complete to gain access?

Answer 1

At the third mission in that quest "In Service of Yalahar Quest"
Mission 03: Death to the Deathbringer  
From here onwards you will be able to do the mission following Palimuth (good side) or Yalahari (Azerus) (bad side). The difficulty is the same for both sides but achievements differ. You will still need to ask mission of Palimuth even if you choose to not help him, otherwise sealed doors will not open.