Taking mass transit in New York City is like being an extra in an endless movie trailer — disaster or horror, take your pick. Here we are, derailed under the East River. Here we are, stampeding because of a shots-fired false alarm in the hellhole of Penn Station. Now we’re all cheek-to-cheek-to-cheek in a rush-hour subway car, praying in the rot and gloom for the far-off day we cease being held by the dispatcher.