When you access into the door by the reader, then you should go out .
There are two ways to leave out.
One is by the reader too, the same as to access the door. The other one is by the exit button. It means that when you want to open the door to leave, you should press the exit button, then the door will open.
There are many different exit buttons. Some are in metal and some are in plastic . The metal exit button looks very nice and they should be suitable for some project .