Oh, it's even worse for the part of the lines that you can't see from this pic. Multiple lines of people with plexiglass walls to the right and left, a wide elevator bank behind (in between two groups of people in line--the one pictured and the one on the opposite side of the elevators), and a row of NOSs and WTMDs in front...and beyond those, the tram station.

So if anything crazy happened inside that area (gunman, bomb, whatever), those people pretty much have nowhere to go, other than to backtrack and stampede the lines of people in the pic.