AUST Hendry building surveying consultants advise that two exits are required in buildings exceeding an effective height of 25m. In a high rise building exceeding 25m, BCA Clause D1.2(g)(ii) requires every occupant to have access to two exits without passing through another sole occupancy unit.
Even though there may be only one tenant occupying the whole floor, occupants (general public) within the lift lobby do not have access to stair 2. The door is therefore not permitted unless in an emergency (fire alarm) the door lock deactivates and allows unrestricted access into the corridor to access the stair 2. An exit sign would be required above the door.
The following illustration depicts occupant access to two exits in a high rise office building: