Reduced mobility and drawing the center-line knife

One question that seems to get asked a lot is why one should carry a fixed blade center-line. There's a number of reasons for this mode of carry, but one of the primary ones is the ability to draw the knife when the ability to freely move and articulate your arms has been compromised. Now, this can be because you're pressed up against a wall, tied up with an assailant, or just any other situation where your mobility is restricted.
With certain sheath systems, the knife is carried with the handle at a downward angle, which works extremely well. The drawback to that is that it somewhat increases the amount of real estate the knife takes up on your belt in the vertical plane and it can also compromise concealability.
The shock cord attachment system that I've come up with solves some of these issues by keeping the knife horizontally on the belt, minimizing the profile, but allowing for enough flex that you can draw the knife with effectively zero articulation of your elbow. You will see that demonstrated in the below video.