Ha ha ha, this reminds me of Space Balls where Pizza the Hut ate himself to death when he got locked in a hot car.
In all seriousness though, there is something a tad impossible about that way of committing suicide. You'd get past the first jugular and then you'd pass out/bleed out and that doesnt count once you cut your own spinal cord you wouldnt have control over your arms. Im not sure this guy could have gotten his own head entirely off his body on his own.
I hear you. There is no way anyone could decapitate themselves.