When I was working on my long stale criminal investigation degree, my area of focus was radicalism and terrorism. And I shook my head every time I read things like "don't rally, might be a target".
To quote Sherman Potter, "Bushwah!" That makes sense if you are facing someone with a mortar or grenade launcher. With small arms, easy enough just to pot the suits as they run. Let the guys without ties go- power to the people, man! <img src="/images/graemlins/smile.gif" alt="" />
IMHO, I'm more worried about a solid head count than I am about guys with rifles. If it is a blast, my concern is making sure everyone is out, and if not, finding out where they were last time they were seen, so when the fire crew shows up, I can give them a decently accurate report. If it is a bomb threat, I want to know were some of my people with bad hearts are real fast, and "Run and hide, there might be a sniper" doesn't help.
I am concented about secondaries, though. Pick a good rally point. Away from cars- to easy to put something small and magnetic, about the size of an altoids tin, under the fill hole.