Vigorous VanCleef Vindicator

Voila! In view a verily vexing vixen, cast vicariously as both victim and villain by the vicissitudes of fate. Her visage, no mere vestige of vanity, is a visage for the vindication of “vox populi”. However, her" valorous" visitation of a bygone vexation stands vivified, and has vowed to vanquish these venal and virulent vermin, veterans of vice and vouchsafing violence she visited verily, a violence most vicious and voracious, visited vigorously upon her pater most vigilant. Her only verdict is vengeance; a vendetta, held as a votive not in vain, for the value and veracity of such shall one day vindicate the victims of the virtuous.
Verily this vichyssoise of verbiage veers most verbose, so let me simply add that her name is Vanessa VanCleef, but you may call her V.

I just wanted to say, as a level 100, this is easy, but nothing here I saw explained what to do for this achievement simply. After killing Ripsnarl and Cookie, a letter shows up on the ground next to where you killed Cookie. You click it, the lady appears, you fight her, she puts you in this nightmare state.

Then all you do is fight your way back to the ship at the end again, fighting some bosses. Easy. But avoid things like fire, they slow you down considerably. That's basically it, kill the stuff, wait for the doors to open in each section, go on to the next. I have no trouble making it back to her in time to engage.

This is how we did it easily:

Step 1. Right after you are freed from the cauldron jump down ASAP, this way you get to the first boss before the fires even spawn.

EDIT: Since 4.0.6. it might not be best idea to jump down asap, because the fires spawn now much faster in the start, so you can't reach first boss before the fires come anymore.

Step 2. Kill the the boss normally, make sure your tank keeps kiting it away from frozen spots.

Step 3. Kill Helix normally, bunch up and nuke just boss while ignoring the adds (We used Heroism / Bloodlust here).

Step 4. Wait till the spinning electronic things spawn before you start moving. Then just move carefully to the Reaver boss. After the reaver boss is dead you should have around 2 minutes left on timer.

NEXT follow either a or b.

Step 5. a. If you have Shaman or Warlock, tell them to either use Ankh or Soulstone (Make sure shamans Ankh is off CD) and after the 3rd boss is dead and the last nightmare starts tell the Shaman or Soulstoned person mount and run to the ship, were the Vanessa is.
Step 5 b. Simply do not save the next NPC and wait till you guys wipe, this is a slower way to do it.

Step 6. a. Make sure you don't save the NPC, then you will be wiped and then DO NOT RELEASE. After the wipe shaman or soulstoned person should self-ress and then simply walk to the Vanessa. Achievement completed!
Step 6. b. Assign someone to ress asap after the wipe, walk back in, use the teleporter to the ship and simply engage Venssa. Achievement completed!

P.S. If you fail first time, you can simply wait 30 minutes and come back again and all of the trash will be back and the Vanessa letter will be there.