1. Take 10 dps, no need for healers or tanks the boss has to die within 6 seconds.
2. Clear up to Algalon you no longer need a key.
3. Pull Algalon and intentionally wipe as the RP is too long if you do not wipe and the system automatically detects your gear level.
4. Run back inside and have your raid group stack on the boss.
5. Do a ready check, countdown everyone to blow all their cds.
6. The bos
s will go into an RP phase again however it only lasts a short amount of time now, so there is no loss if you blow every cool down before his RP is over it is probably best so you do not waste a global when he becomes active and risk the encounter being to long however it should not be if everyone can burst 100k dps and do around 1.4k Raid DPS.
7. Use every CD, kill the boss within 6 seconds of him becoming attack-able and you should get the Feat of Strength, don't hesitate if it takes a few seconds for it to pop up as you need to wait for the encounter to finish.
I accept no credit for finding this, I am just offering a clear guide.

Enjoy.
( I got it on EU )