I am wandering around the underworld, (looks like i missed getting the wizard loose) and when I saw an opportunity to exit the map I took it (basically a chicken shit at heart) Well thats when the Mindflayers got me. I have fingered out how to capture the flayers,with the control crowns and i have liberated the slaves...but noe of us can get out! Did I need the key before I got there? please help!

No, you don't. The exit door will open once you kill the elder brain, who is in the northwest part of the dungeon. Make sure you have one flayer alive to open the door which leads to where he is. It's a pretty tough fight so be prepared!

No key available or needed. In order to get out, you wil have to finish clearing the flayer city and destroy the elder brain. There is going to be two major snags. I'm sure you noticed the door that says you need someone of exceptional brainpower or strength. To get through this door, there are 2 options. 1) Have a flayer under contol walk right up to the door. If you don't have any more flayers under control, use option 2. 2) Change into the slayer and open the door. I found the part after this to be one of the hardest parts of the game. Best of luck to you.

Can't you use a Draw uponb the holy might spell to get 25 strength and bash the f*ckin' door

Or a cheated crom faeyr

sidenote : i have 25 strength and a thief with 180 lockpick both didnt helped me to open this
and numerous other doors =(

I believe Lora's talking about the exit door that won't open until you kill the Elder Brain. Every other door you can open with 25 strength or a charmed flayer.

There always will be Mindflayers left, in the room above slaveroom where you got the oil(?), once you killed the minflayer and left the room there would be teleported anoter one. Use a collar which you can find in the slaveroom and the easiest way is get a character invisible and use it as a quick item, and get the mindflayer open the
door for you. Beware, once he/she/it opens the door it turns hostile.
Good luck.