I worked in a city hospital that installed 2 inch thick bulletproof glass in the window at triage, the first place folks come to on their way to the ER. First issue was that they installed the bulletproof door and window in walls that were otherwise made out of metal studs and sheet rock, neither noted for their missile-proof qualities. There was also a 6 inch hole in the middle of the window, designed to permit conversation between nurse and patient.The hole was protected by a metal grill-which grill pretty well precluded the passage of intelligible speech. So they removed the grill, leaving a hand and handgun sized hole in the middle of bulletproof glass, surrounded by non-bullet-proof wall. Beware the false security conferred by half-measures-