I’m not sure if this is a bug or I did someting wrong, but this doesn’t affect my gameplay.
I built a parking lot at level -1 and -2 with the subway station on level -2. There are the escalators in all floors connected with the path to the terminal. I finished the hallway with escalators first and everything look just fine, following with the hallway with elevator a hundred meters further away from the subway. Once the elevator is completed, most of the passengers took the elevator down to the level -2, then walked back to the subway.
Employees, people who parked their cars, and anyone in level -1 already have a shortest path and sometimes prefer the elevator, but most of the people who were coming from a subway station that is placed just right next to the escalator walked a 100 meters further away just to take the elevator and go straight to the ground, then walked another hundred meters to enter the terminal.
So I made the path a little bit longer , this is how they walk. ( Longer than that will make them prefer escalators again. )