It’s extremely amusing to see a professional display proper gun control and safety. He must have had a magazine in the weapon, locked the slide to the rear, looked in the chamber and saw an empty chamber, and then when he let the slide go forward, he chambered a round. He never noticed that his empty weapon had a magazine in it. Incredible!

The police officer did three things wrong:
He must have pulled the trigger
Gun loaded (even though they think it's not)
Finger must have been on the trigger even though he wasn't covering a target

I think he got the point of gun safety across to the kids!