I grew up in New York City, and rode the subways until I finally escaped the city at 18. You learn to never, never, NEVER stand near the edge of the platform as a train nears a crowded station. You also develop the instinct to look behind you as the train enters the station, regardless of the number of people on the platform (I still practice this in every train station I’m in, even though I no longer live in NYC).
Of course, as a native New Yorker, it’s ingrained in you since late childhood to never be unaware of your surroundings. I’ve been away from there for over 30 years now and still practice that.
And you never look anyone in the eyes.