[His gaze flicks down to the gun and an eyebrow goes up, before he remembers that not everyone here is dragged from contemporary Earth, so he supplies:]

It's a rifle. Projectile weapon.

[The basic summary, since they likely don't have time to get into a proper explanation of guns.]

You could've, you know, said something. Who goes about tackling random people?

[The voice, God's voice, interjects:

You had best come to me, Crowley, or you'll do worse than fall.

Crowley rolls his eyes.]

Fuck off, mum!