This isn't the first time that Lee Jung-jae and Gong Yoo (The Salesman) have shared the screen, as they had an intense sequence in Season 1 where The Salesman slaps Gi-hun (which

The detail was first spotted by someone on Reddit, who pointed out that in the first round where there’s only one bullet in the chamber, it’s actually a dummy bullet and would never have gone off. You can tell the bullet is a dummy one as there’s a hole in the middle of the bullet caused by the primer having already been hit by the firing pin.