How do i get out?


I have the hilt of the equalizer
I have slept once am i allowed to do that?

Yes you can sleep in the mind flayer region (though keep in mind that if you are doing this as the matron mother's quest to get the elder orb brain you have only three days (I think) to do it, so don't sleep too often).

To get out there are a number of things you need to do. You should have spoken to the githyanki who explained about the doors and needing to kill the elder brain to open the exit doors. Most doors in here are only openable by changing into the slayer or by a mind flayer, which you can do by using the control circlets (obtained in the slaves area, bottom right). Then you just need to explore around until you find the elder brain and kill it, which will open all the doors.

you can sleep as often as you want, but to get out, you have to do several things... (Spoilers ahead)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
First, there is one room, in which a mindflayer respawns permanent. Here you can collect some kind of liquid
Put this into the strange machinery in the room with the sleeping slaves. Now the slaves are free and the boss tells you, what to do further.
Yoe will get then 4 neglaces, which controls mindflayers. Search one and charm him with the neglace. Then you can open some doors, which only a flayer can open. There are then several fights, until you get to the elder brain. Destroy it and you are free to leave.
And don't waste the neglaces... Sometimes the flayers get hostile again, so you will need another. And without a flayer under your control, no doors will open.

OK, this is long verion. But iirc, there is an other method in slayer form to get out. But this I never tried, so maybe one of the other guys here can give you some hints.

Oh, I didn't know, that there is a time limit in killing the elder brain, but anyway I fished everything normally well under 3 days.

The time limit should be stated in your journal.