There is an achievement for 5v5 called last man standing. Last Man Standing - Achievement - World of Warcraft
Healers generally will have a hard time getting this achievement because it requires you to be the only one alive at the end of a 5v5 match.
An easy way to get this without risk is to do this:
1. Designate who will get the achievement.
2. Generally the other teams DK will always die last. When he goes into ghoul form, have your team except the one designated leave.
3. Kill the ghoul. (if he corpse explodes or releases, you will still get it)
That's it!