Continuing in a series of strange things that I have seen while consulting at hospitals…
If you look closely enough, you will notice a set of medical gas shutoff valves behind this cross-corridor door that is held open. Even though the door has a window (or vision panel, as NFPA calls it), and you can actually see the medical gas shutoff valves through the window, it is still a violation.
NFPA 99-2012, section 126.96.36.199.4 says zone valve boxes shall be installed where they are visible and accessible at all times. Well, I think you could say the zone valve box in this picture is visible, but it certainly is not accessible as long as the door is held open.
Section 188.8.131.52.5 speaks more directly to this issue: Zone valve boxes shall not be installed behind normally open or normally closed doors.