As this skydiver was tracking away at break-off, they noticed an open canopy below them at the last second just as they were about to deploy, so they kept tracking to get clean airspace and avoid a mid-air collision. Not cool.
Why did it happen
Drift / Movement / Backslide
One of these two groups may have slid into the other’s airspace. Either the first/lower group accidentally moved up jump run or the second/higher group moved down jump run.
Another potential cause for this incident was a lack of separation. If the second group rushed their count or wasn’t aware of ground speed, it’s very possible that they got out too quickly and were in freefall almost directly over the group which exited before them.
How could it be prevented
While on the ground, jumpers should check what direction the aircraft will be traveling for jump run. Then, after exiting the plane, they should ensure that their movements are perpendicular to that direction. Notably, this is particularly challenging while doing a solo jump because it is difficult to know whether you’re sliding around. (That’s why more experienced jumpers cringe when they hear the words “solo freefly” while in the loading area.)
Proper Count For Exit Separation
Many planes have those handy-dandy signs that tell you “If ground speed is X, allow for Y seconds of separation.” If you ignore them and get out on top of the group before you, this is what can happen. Further, many newer jumpers get excited about getting out the door and count a very quick “ONE-TWO-THREE-FOUR-FIVE-EXIT!!!” instead of a calm and accurate “One Thousand… Two Thousand… Three Thousand… Four Thousand… Five Thousand… Exit.” An experienced jumper who viewed this video said that one way for younger jumpers to avoid this issue is by counting out loud; it’s harder to rush the count if you’re vocalizing it.
Tracking vs. Pitching
This jumper – who did one hell of a job noticing that canopy deploying under them – made a very quick decision to track further and tried to get past the other jumper. Some people may say the correct decision would have been to immediately deploy. Both arguments have some validity but by tracking further this jumper avoided the possibility of a slow deployment, snivel, or high-speed malfunction that might have caused a collision with the lower jumper. Personally, given that he still had altitude, I think this was probably the better choice.