Fifth floor

Sixteen steps and a turn after entering the stairs, the figure reached the second floor of the Terrace Heights Apartments.  It stepped out into a dimly lit corridor with four doors.  It looked down the hallway.  After a short pause, it turned and continued up the stairs.  Another sixteen steps and another turn after entering the stairs, the figure reached the third floor of the Terrace Heights Apartments.  It stepped out into a dimly lit corridor with four doors. Twice more the figure repeated the process until it reached the fifth and top floor.  Reaching into a pocket, it pulled out a key.  It approached a door and inserted the key.