If the customer "forgot" he had a round in the chamber, he was unfit to be a police officer.
If he knew it was there and "forgot" to say so, ditto.
The employee certainly should have checked, and certainly should have placed it where no one could walk in front, OR, pointed it in the safest direction possible and cautioned everyone to avoid the muzzle.
The military rule, which I can't forget after running arms rooms numerous times, which I always follow, is that the armorer assembles or clears the weapon, hands it to the recipient, who clears the weapon. Upon return, the procedure is repeated.
If you come to my house to look at weapons, I will clear the chamber visually, hand you the weapon open and insist you verify same, and repeat upon return.
This is not "paranoia," this is SAFETY. EVEN FOR WEAPONS THAT AMMO NO LONGER IS MADE FOR, OR ARE NONFUNCTIONAL.
There was no "accident" here. There was NEGLIGENCE on one or more party's part--either customer for not noting condition, employee for not checking, or the poor guy who walked in front of a muzzle.
"Oh, but what if there's no safe place to point it?"
Then you don't run a gun store. End of discussion.
As Pusher says, a clearing barrel can be made from a $5 scrap barrel, some arc-welded supports, $5 in sand and a can of spray paint. A 5 gal drum of sand suffices for pistols.