Way in — way out (4)
I believe the answer is:
door
This clue is a double definition.
'way in' is the first definition.
(I've seen this in another clue)
'way out' is the second definition.
(way in or out of a building)
(Other definitions for door that I've seen before include "Barrier to open and close" , "Entrance way" , "Entrance barrier" , "Entrance to room, house etc" , "Jim Morrison?" .)