Some years ago, I was curious about the whole Glock thing. After the clerk gave me the whole Glock spiel ( I guess that would be the "Glockenspiel" ), he racked the slide before handing me a pistol. And a round popped out. He froze, popped out the mag ... which was fully loaded.
The clerk said "<removed>", apologized, made a comment about maybe the store owner took the new gun to the range, and we went on to look at other things. ( I didn't bother mentioning that if the shop owner took the gun to the range it's not exactly "new" anymore).
Point being that stuff happens for any number of reasons, even the ridiculous. A firearm should never ever ever be pointed in an unsafe manner, and any store employee that does so should probably rethink what they're doing in that job.
Speaking of gun store owners, when I recently picked up my Colt Series 70, several blips happened. While the store clerk finished up the paperwork, he laid the 1911 on the counter, muzzle pointed at my groin. He quickly recovered with a grimace and said "oops, not good" and swiveled the gun to point away from anyone, including my special area ... OK, ... two minutes later, the shop owner was handed a .44 revolver in a rug. The owner proceeded to take it out, fondle it, work the action, all while pointed square at my chest. I softly noted that I was sure glad he checked to see if it was loaded (which he of course hadn't). He cleared his throat and moved off to the sidelines. The clerk quietly said to me "good for you. Boss man doesn't like to be correct by us worker bees."
So, the firearms safety rules have a corollary - don't just keep an eye on what you're doing, but be very mindful of what your neighbors are doing ...