If it's just that staircase, then why wouldn't she go to another entrance? There are at least 2 for every station.
Also, where the fuck is that water pooling if the trains are still running through the station properly? I assume there's a ramp leading upwards from the turnstile.
Never saw anything like that in my 2 years in Brooklyn, but I also stayed in Flatbush, and hardly ever went into Manhattan. By far, my biggest gripe with the NYC subway was the weekend schedule. They cut the frequency of the lines drastically, under the guise of "maintenance". Bullshit, you're just cutting costs. My travel time would almost double on weekends, mostly due to waiting longer for trains to arrive. Fucking horrible. Almost defeats the purpose of a mass transit system if it's only an efficient form of travel 5 days of the week.