Alright. I got one. Might not be a "horror story" to more experienced healers, but to me it was a mess.

Last night I ran the Vault for the first time on my WHM (I typically Tank, not heal). I'm still a little gimpy geared for it. Told the group. They were cool. Got to first boss with everything going smooth. Do the first pull at the top of the stairs and the Tank's Hp start dropping like crazy. I'm spamming cure II but can't keep him up. I Pop bene at his bottom 10%. He still dies, and I'm at a loss because I've literally used everything I could to keep this guy alive.

Found out it wasn't my fault. It turned out he was Dc'ing and my casts weren't actually healing him. One of the Dps were in voice chat with the guy, and said so... just before he bailed.

K. No prob.

The last Dps and I votekick the tank and look for party members. We get a Dps quickly, wait for 10 min, still no Tank. The Dps get edgy and decide we should continue on without a Tank. I end up having to heal everything from the second pull (that includes the top of the stairs, since nothing had died before the first Tank Dc'd) all the way to the second boss room while playing the role of paper tank with the Dps (those giant knights and chess piece knights hurt, by the way).

We get a second tank just before the next boss... who proceeds to stand in almost every AoE the guy televises, turns cleaves towards the Dps and me (wanted to make sure I was awake, I guess), and then speed pulls the rest of the dungeon all the way to final boss with almost no Cd's. He pulls the final boss before the Dps are even at the door, and then proceeds to stand in the charge line of every single Knight and is almost constantly slowed or bleeding. My Mp was sucking empty for the entire last 25% of the fight. Fight ends. Tank busts out of there before the loot box is even open. Dps speaks up and says, "anyone else think that run was going smoother before we got a Tank?"

Yes... Yes it was.