Okay this was private last time and not many ppls know it but because many servers got it fixed il post.
It was working or maby if u have luck it works on Mangos last rev.
1)Okay soo first get ress sickness
2) Go to dire maul:
Dire Maul - Zone - World of Warcraft
3) go to immol'thar boss:
Immol'thar - NPC - World of Warcraft
4) Atack him and in time u fight with him he will put on you a debuff that it's this:
Infected Bite - Spell - World of Warcraft
5) now when you have the debuff on you die and u will see the debuff dont dissapear
6) Re enter in instance and revive, now the debuff wont be visible but u will be invincible, (when i say invincible i mean the moobs can atack u but they wont do any dmg to u, LAST untill you relog)
Good luck