Make It Count

A few key points to keep in mind for the time between the end of the first kill to the engagement of the last boss:

1. 
   
2. Make sure everyone knows what drake they are getting ahead of time, and which cage the NPC with their drake comes out of.
3. 
   
5. 
   
6. Don't loot ANY corpses. The boss loot will be there when you're done.
7. 
   
9. 
   
10. Chain pull. If you're using any forms of CC have a plan ahead of time who is going to take care of what (i.e.: Shaman Hexes and Mage Sheeps back two Humanoids on construct pulls). This will help save time since you won't have to mark anything.
11. 
    
13. 
    
14. Don't be afraid to kill a few dragons on the way to the outer platforms for the constucts and second boss. Better to take a few seconds to knock out the 3 or 4 you might aggro than to ignore them and have someone die as a result.
15. 
    
17. 
    
18. If you have a Blood Lust/Heroism, use it on the second boss. This will be the best use because this fight is slightly more stationary than the third.
19. 
    
21. 
    
22. On the beast pack the third boss spawns: Kill the Wind Serpents first (chain lightning), followed by the Mammoth (charge).
23. 
    
25. 
    
26. Once the third boss is dead, everyone who isn't buffing Drakes needs to immediately mount up. The buffers need to cast as soon as possible. When everyone is ready you need to immediately go up and engage the boss.
27. 
    
29. 
    
30. If any Whelps aggro on the way, let the Ruby Drake take care of them as long as he keeps his second and third ability up constantly since he more than likely won't have aggro most of the time.
31. 
    

Our dragon makeup was 1 Ruby, 2 Emerald, and 2 Amber then finished with about 2 minutes left. But your group should do whatever you feel most comfortable doing. Ours was one of the more reliable makeups, 5 Amber is very fast but takes practice to perfect it.

Just keep calm and you'll win. Good luck!

It's fairly difficult, but seems quite possible. The important thing is that you need as little downtime as possible - essentially chain pulling, similar to the Strath timed event.

This is how I'd do it:

1. As soon as the first boss dies, everyone grabs an amber drake. These are the dps mounts, and are all you need for the few azure drakes you'll need to kill.
2. To actually kill the azure drakes, open with a time shock, then time stop, then do a heavy time shock (due to the charges on the mob). Repeat on any subsequent mobs, with other drakes using time stop.
3. Kill as few drakes as possible - this is achieved by flying directly up at the start, and flying out and around.
4. Kill the eastern constructs, the western constructs, then travel around the inner circle from southwest to southeast. Use as little CC as possible, and kill the casters first. Move out of blizzards/flamestrikes.
5. Kill only the drakes near enough to the second boss' platform to aggro during battle, drop down and engage. Kill, quickly loot, fly to the third boss.
6. Fly between the four third boss positions, loot, fly back to the drake vendor and pick up two ambers, two emeralds and a ruby.
7. Kill Eregos as expediently as possible. One amber should constantly use temporal rift (except for when they have 7+ charges, at which time they should lance) and the other should be constantly lancing to build up the other amber's charges - it's very unlikely with the damage from the two greens and the red that both could channel temporal rift and get charges.

The keys to success with these achievement likely lie in: a) the people in the group having done the instance before, being able to chain pull, and not aggroing unnecessary drakes during the period between the first and second bosses, and b) the people in the group being skilled enough with their drakes that they can one shot Eregos, and quickly.

I'll be trying for this achievement shortly as I'm closing in on my red proto, and I'll let everyone know if it's successful.

This strat was originally posted by Whispah:

First off zone in to the instance on Normal and kill the First boss and get your appropriate drakes (whatever your group wants provided you can kill it one shot with the drakes of your choice).

Once this is completed die and release (don't zone out, just die). When everyones released, set it to Heroic. Everyone zones in with their drakes. You now fly around and kill all bar one pack of constructs.

Then kill the first boss, kill the last pack of constructs, kill second boss, third boss and then huzzah.. final boss.

I have no idea why it was rated down and purged since it stills works as of 01/17/09.

As of 3.0.8 this no longer works.