Probably helps add a certain gravitas.

Because they worry about any other weapon? Or the extremely rare case that someone actually has a highly dangerous fire arm? My point is that they can have much less drastic standard procedures (and equipment), because the standard scenario of operation is significantly less threatening.

There are special forces that get involved with the real shit. But the bar for real shit here is someone has any gun.

Guns aren’t the only thing that can cause bodily harm.