Hi Matt,
Wow, that could have been very bad. Glad you had your FAK with you. I'm glad it wasn't worse, and hope you heal up quickly.
I grabbed my sebenza with my right hand and flicked it open with my wrist and was cutting bags with one smooth motion.
I wonder if this isn't the real moral of the story. Whenever I "flick" my knives open, it creates vibration shock in my hand, and I have less surety about the lock, since part of what I'm feeling and hearing is not the lock but, rather, the blade itself opening. When I do that, the blade makes a good click even when the lock does not, so I'm not always sure which I'm really hearing or feeling.
However, when I use the thumb stud and smoothly open the blade, the blade itself makes no vibration or sound and the only click I feel or hear is the lock engaging. I would think that, for maximum surety, and
especially in a noisy environment, it would be important not to flick the blade, as fun as that may be, but to calmly and gently push the blade into position with your thumb until you feel the click of the lock engaging.