where in the world is harold?

Harold came in with his son.  Harold was very old and he was struggling. Depressed, not eating, just not doing well.  He needed help. Poor guy.

So back he went, Harold and his son.  They saw the nurse, the doctor.  Had a more comphrehensive assessment by someone from mental health.  Now it was time to wait.  Son decided to go out to the car to get something, leaving Dad alone.

Dad got up, maybe looking for the restroom or looking for his son.  He wandered down the hall.  He ended up going through a door by triage.  Here's the thing: It was a door to a stairwell. The problem is you can enter the stairwell, but you can't come back into the ER. The door doesn't open.

So there is Harold, in the stairwell, no doubt looking for a way out.  Never shouted, pounded on the door.  Of course, the nurse discovered he was gone. Looked everywhere..eventually had the hospital operator page for him to come back to the ER.  An alert gray was called (an old person wanders off). Didn't  find him.

Well it just so happens there was a inpatient doctor in the ER.  He was leaving and decided to walk up the stairs.  He went into the stairwell where Harold had gone. There was Harold standing there looking lost.  He was brought back into the ER and everybody lived happily ever after.

The thing is: What if that doctor had decided to take the elevator instead? How long would it have been before someone discovered Harold?