Last week, a coworker offered up a ticket to a show he couldn’t make it to anymore – and at a steep discount, to boot. Without plans and with a newfound insistence on soaking up every experience to come my way, I snapped it up. Which is how I found myself setting out at 10pm on a Tuesday night for an immersive theater experience in a converted out-patient hospital in Brooklyn. Because of course. The show is Then She Fell (NYTimes Review), and it’s akin to the likes of Sleep No More, the kind of theater without stage or seats or curtains or concessions. The kind of theater with a…