Suspension Competition Entry #14 with the information provided by the submitter:

Information about the entry: This shot was taken in the New York City Subway system, on the J train, crossing over the Williamsburg Bridge. Due to police being present at stations before and after the bridge, we had a 3 minute window to get people up and bring them down and walk off the train like nothing happened. People that witnessed this on the train didn’t rat us out, and were thoroughly impressed, except for the one guy that turned his head away and convinced himself that we didn’t exist.