On skydive number 30, this new jumper had his first attempt at back-flying and sit-flying while still using student gear (yes, we all know what happened next). His container – which was, predictably, not freefly-friendly – had a premature deployment. The deployment bag went straight into the jumper’s hands and he actually managed to catch it. Initially he thought he was "holding onto his harness," but once he realized what had happened, he let the deployment bag go and – somehow – had a clean opening that he was able to land safely.
There is a reason that some gear is called “freefly friendly” and some gear is not. When gear is not freefly-friendly it is typically because, if taken into orientations other than belly, it runs the risk of prematurely opening. Generally, a lot of student and rental rigs are not freefly-friendly and many dropzones have rules against students freeflying for this exact reason.
We don’t actually know if this student communicated their intent to a coach, instructor or more experienced jumper. We are assuming they didn’t because most jumpers who have been around for a minute would have told this jumper that attempting to sitfly/backfly on a student rig that wasn’t freefly-friendly was not okay.
Not all training programs are created equal and some AFF instructors never really tell their students about how to progress into other disciplines. This oversight can lead to newer jumpers potentially not understanding the different ways that certain orientations interact with the air. Again, we don’t know if that happened here but it’s something to keep in mind.