At least, I think it's a guardhouse. It's an unused structure near the southwest entrance. I couldn't find any information on what it actually is or was.
Construction cranes building an addition to NYU Langone Hospital. The hospital is on the Hudson River and was still rebuilding after 2012's Superstorm Sandy. Sketched from the 9th floor Family Lounge at the NICU, where I spent a lot of time last summer.