Well, I just did the Warehouse today. Let me re-phrase. I just got to the tenth floor and bailed on the Warehouse today. I could not find an accurate guide beforehand--the one I did find on Central seemed out of date--several of the things described did not happen, it didn't mention the global spell issue (if you use a global spell on the last floor, the boss will cast Rebirth and bring the dead rats back to life...sigh). I confess we only had three people, not four--it's kind of hard to find people who want to dedicate three hours of their day to this craziness--so perhaps we were doomed from the start. Anyway, if anyone knows of an up-to-date guide, I'd also appreciate a link.
Do not use global attack spells. Kill the rats first, one at a time to get rid of the towers. Next kill the cat. Remember, you can heal if the LIVING opponents are already at full health or close to it. When they heal it does not bring back any that are already dead.
If you die during the battle, FLEE, use a potion to heal and then re enter the tower ALONE. You will be able to run back up the levels and rejoin the battle.
hp1055cm: Thanks again for another helpful reply. I will probably not try this again till I get to level 56 or so...too hard without critical capability, I think. But I didn't know you could flee and come back. Useful tip. I'll take a look at the guide when I can bring myself to revisit the experience...even in theory. :x It was a major downer to spend over two hours in that place and then have to bail. After surviving the quasi-apocalyptic Storm Lord attacks on the fifth floor...but after the 10th-floor boss cast Rebirth we were just too demoralized to go on! Another day, perhaps...