If you can’t or don’t want to see it, it’s a video of Glock Team captain KC Eusebio shooting a stage at an indoor shooting range. As KC was moving to a new position, a magazine was on the concrete floor… and wound up under his foot. He slipped, landed on his side, got to his knees, and finished the course of fire.
Nice work.
Many things to take from this.
First, his trigger discipline. He was moving, so his finger was off the trigger and out of the trigger guard, indexed along the frame. Think about falling like that – you’re fingers are going to go, and if they were on the trigger….
Second, his muzzles discipline. He kept the muzzle pointed in a safe direction at all times, even while he was falling and recovering.
Both of these things take practice (mostly on the finger positioning, making it habit that when you are off the target you are fully off the trigger, indexed along the frame/slide), and awareness of what you are doing and your gun is doing. Focus.
It also shows that despite something totally unexpected happening, you keep going. He didn’t give up. He didn’t stop and laugh, or freeze, or go “oh shit”, nor did he let the pain stop him (obviously it hurt, given his actions after the shooting was over). I’m sure there was a bit of a “oh shit” in his head, but he maintained his action and finished the string. He stayed in, until things were truly over.
Really awesome performance.
Stuff From Hsoi 
Good job, KC.
I once took a sidestep with my finger on the trigger (my sights were on the target, just wanted a slightly better angle), and was told if I did that again I would be DQ’d. Good SO’s will build a higher level of safety into you, it becomes automatic after a while.
That range is definitely begging for some kind of high traction coating. Next time, it might not be someone as skilled and strong as KC.