Elemental Bonds: Doubt

I can't believe no one has explained what you're actually supposed to do in this quest. People here talking about PvP and bugs and whatnot, but nothing about what the quest is all about.

In short terms: Let Cyclonas take you to the tower where Thrall is levitating on the top floor. Next, take out those normal elemental mobs, one at a time. They respawn all the time, so avoid AOE, since it will generate too much damage that you can endure in the long run. Continue to kill mobs this way until the quest says it's complete. Nothing else to it.

The only usable information I found here is the good gentleman putting the entire NPC conversation between Thrall and Aggra, which you can follow as an indication of how many mobs you have to kill till the quest is complete.

If you abandon this quest, you can not pick it back up from Aggra. You will need to find Cyclonas. He is on the Bluff of the South Wind in Uldum, which is south of Neferset City. Cords are 47, 88. He will also give you another ride back up to the quest area if you need.

I'm not quite sure why this is shown as the last quest in the chain. This Thrall/Aggra chain actually is far longer. The full chain runs as follows:

1. 
   
2. The Call Of The World Shaman
3. 
   
4. The Nordrassil Summit
5. 
   
6. Into Slashing Winds
7. 
   
8. Doubt
9. 
   
10. Into Coaxing Tides
11. 
    
12. Desire
13. 
    
14. Into Constant Earth
15. 
    
16. Patience
17. 
    
18. Into Unrelenting Flame
19. 
    
20. Fury
21. 
    
22. The Vow
23. 
    

The quest reward from the final quest is your choice a very nice cloak appropriate your class and role.