in the 14 months since a gunman opened fire at that elementary school in newtown, connecticut, there have been at least 44 school shootings. as a society, we've had to make a choice about what our response will be. whatever political will there was to regulate some of the most lax gun laws in the world in the aftermath of new town was quickly and deftly extinguished. so this is what we're doing instead. >> yep. >> let me in. please. >> what you are watching is exclusive footage from nbc news of an active shooter drill. it is being performed in the halls of troy buchanan high school in troy, missouri, a school about an hour northwest of st. louis. it's the 13th such drill the school district has staged in the past year. and the victims are students. all volunteers. >> we heard the banging and all of that so, i mean, we knew that they were there and had to be