These two skydivers did a wagon wheel exit through some clouds (more on that later!). After they let go, one of the jumpers went to their back and suddenly, BAM! Open canopy! He had a very hard opening and was knocked unconscious. Additionally, he suffered a collapsed lung, three broken ribs, and in his words, "Miraculously I didn't break my spine!!!" Fortunately, he woke up in the air under canopy, found the dropzone and landed. He then spent five days in the hospital, three weeks on strong painkillers, and a year of rehabilitation before being able to jump again.
We're just going to directly quote the text that was provided with the submission: "There was no freefly friendly system! And the system had a very loose pocket where the pilot chute is." In other words, this jumper knew full well that this gear was not in proper working order for the type of jump they were doing but decided to jump it anyway. The fact that they were doing a wagon wheel exit — which is notorious for resulting in equipment rubbing up on the airframe — only underscores this issue.
You wouldn't go on a competition belly four-way in a wingsuit and you wouldn't attempt a speed skydive in your baggiest gear. Well, in that vein, you shouldn't be doing a jump where your back is going to be exposed to the wind if you know your BOC elastic is loose and your rig isn't freefly-friendly.
Based on the metric altimeter we're guessing this video did not come from the United States and we don't know what the cloud clearance regulations are wherever they jumped. However, regardless of where it happened, this video shows exactly why jumping through clouds is dangerous. Had that lower jumper been directly under the cameraman, and had that premie happened while he was obscured by the clouds, the cameraman would have had no heads-up that he was about to have a possibly fatal mid-air collision with a premature deployment.