I know they don't unhinge them... The lower jawbone is connected to a specialized bone called the quadrant bone, that acts as a double hinge held together by ligaments that allow over 150 degrees of movement. Ever try exerting large, single direction forces through a double hinged system? Maintaining proper alignment for optimum bite force is impossible. Even the weak jaw forces of a snake (I've read uncomfirmed reports of 37 psi in the afrock) lead to misalignment. In fact, they were designed for that purpose, so their jaws can "walk" down the prey while swallowing, and allow greater range of movement.
HOWEVER a jaw structure with very powerful muscles would require a rigid system to as not to break the joints during a crushing bite. But snakes have a very intricate/delicate/specialized jaw structure designed not for chomping, but swallowing whole foods. If you were to put those strong jaw muscles on a snake, the jaws would shatter when clinched tight.
I am not saying that a bite from a 20 ft retic isn't a horrid experience... but choosing that over a full grown green moray or tessalata eel eems rediculous. those are limb removing bite/twisting forces. After further research, it seems it was a National Geograghic episode, although I can't seem to find the results of their test.
whew... being a biomedical science major pays off for once!!! all that money was worth something right?