1) you need to be a priest
2) get the holy talent (i think it's spirit of redemption, It makes you to an angel when you die)
3) Die in the BG
4) become the spirit-healer
5) 'AFK' while you still are in this form.

note: when you get out, you will be dead. but it is much better with a 2 min corpserung, than a 15 min desserter