Let's not under estimate the dreaded "tunnel vision", which I believe is a factor in most accidents and incidents.
This incident is a good example. Tunnel vision may have contributed to the pilot focusing on trying to decend through the gap instead of evaluating other options.
Tunnel vision will cause you to fixate on the task you most accustom to do, even if it is difficult to do. So if you are used to unbuckle the parachute in the cockpit, chances are that under the extreme stress of bailout (I can't imagine a more stressful situation as a pilot) tunnel vision will take over and you will unbuckle the parachute even if it is not straight forward. Same goes to if you are used to fly with a chute but occasionally don't , chances are that in an emergency you may bail out without checking if you wearing your chute. I heard stories about pilots bailing out without their chute.

Ramy