Similar to how stairwell doors should open inward towards the stairwell to prevent a pileup from panic outside of it with the exception being the bottom where the floor has access to the outside which should open outward. You'll also never see revolving doors that either don't have regular doors next to them or are of a design that there is a breaking point which allows both sides of the revolving door to be pushed open in an emergency (that piece of code stems from the Cocoanut Grove fire in Boston).