I searched a couple ways and did not see this. If it is a repost, please remove it.
Also the reason why I am posting in exploits is that I feel that being able to use this ability in a duel to get full health again is most certainly not intended.
If you feel this finding is a mistake, then please move to guides or remove it. Thank you.
All you do is have a buddy join a group with you and start a duel. When you want to fill your life, Just cast Void Shift on the guy in your group. And vwahlah. Full health (Pallies are not the only ones with Lay on Hands lol)
It will not work on the person you are actually dueling... Even if they are in your group. But it will work on ANY bystander you can get into a group.
Have fun with it