It’s hard to imagine a building with a 17+ floors not having elevators. And almost as hard to imagine people who have reason to be on the 17th floor not using the elevators instead of the stairs. Possibly the stairs are used for short trips — maybe faster to get from 16 to 17 by stairs than waiting for an elevator. But still . . .
It’s obvious somebody’s trying to send somebody a message.. but who? To whom?