This is the gripe that a lot of us share especially when trying to do our part in a Campaign battle. I've had that happen to me in Rolanberry and Pashow where the healers didn't want to help. As a result, I take a bump and most of them die.
Then the other mage tries to run away and dies in front of another group.
Then the fun begins because while I wait for a raise, if RR was not available, within my view I can see trains of mobs wipe out the field.
It sucks, but when the wipe happens I can't help but to laugh.
I also don't have anything against mages who melee and heal for more EXP yield in Campaign. Hey if you can multi-task and kick some serious arse, go for it. In the end, you'll be heavily rewarded.
But like Flag said, some players seem to have a solo attitude when doing campaign when its supposed to be group effort. Because of that, all these kind of little mishaps occur.