A shocking video posted on social media shows that even the most skilled and experienced shooters can make mistakes with potentially disastrous consequences.

During a shooting competition at London Bridge Action Shooters club in Havasu City, Arizona, in late March a range safety officer starts a string and the shooter can be seen engaging targets around barriers. When he’s several targets in, the shooter notices a fellow competitor still on the course of fire picking up brass, seemingly oblivious of the rounds passing just inches from him.

“Hey, whoa, whoa! What’s going on?” the shooter can be heard saying as he notices the person in his line of fire.

“Stop!” another competitor says.

The downrange competitor doesn’t seem to notice the shooter on the course of fire until it’s almost too late.

“We experienced a very serious safety incident at our last match,” the London Bridge Action Shooters Club said in a statement on Facebook. “A shooter was allowed to make ready and begin shooting a stage, while a person was still downrange. Fortunately, the person was spotted, the shooter stopped, and the incident concluded with no one being hurt or worse.”

“We all should recognize that a stage has poor visibility or an RO is being less-than-diligent and do what we can to improve the situation — an extra set of eyes, a cautionary suggestion,” the club added. “There are not enough people who routinely shoulder this burden. Everyone needs to be involved.”

And the video has shocked the major shooting leagues into reminding its competitors to be diligent.

The video “provides for us an opportunity to remind our members, Safety Officers, Safety Officer Instructors and Match Directors that safety is everyone’s responsibility,” International Defensive Pistol Association director Joyce Wilson said.

“Our Safety Officers have a big responsibility in ensuring that shooters will not be in harm’s way while running a stage,” she added. “This event serves as a reminder that complacency is the enemy of safety.”