edbryan, do not listen to anyone above.
only poymaasin is coorect by saying, they have no rights to keep your passport.
alex brod, you are saying nonsense, as Business visa IS for work. So - edbryan - you DO work legally.
Now. Business visa rules are:
1. within first 30 days from the day of your entry you do not need an exit permit. Just get your passport and leave.
2. If your BV has been extended, and you are in Qatar for more than 30 days, you need an exit permit. Go to your employeer, tell them you don't want to stay, remind them that they have no rights to keep your passport, get an exit permit and leave.