That’s my pet peeve with movies - the obligatory noise with chambering a round - if you watch sometimes it happens more than once. Not saying that the noise doesn’t occur in real life - more saying that the characters in the movie would probably have already had a round in the chamber.
If they don't, they certainly should have one in it & cocked after the third time they jack it.
Joe: "Why didn't you shoot him, when he ran?"
Moe: "I was out of ammo."
JOE: "But, you never fired it! How could you be out of ammo?"
Moe: "I had to jack the slide & put the barrel against his head every time he smart-mouthed me, to show him I was serious. By the time he ran, I was empty. Didn't even have time to cuff him; it would have interfered with the dialog."