Indeed, the Survival Instinct is very hard to overcome and don't be too hard on yourself. As some members on here have experienced, even with a reliable method, the SI is oftenly too strong that it prevents the final step (whether it be the 3/4 inch of a trigger pull, the last step before falling off a height, holding on to the last minute or so for the ligature (hanging), etc.) from being taken.
I share the same sentiments as well, and while I don't want others to use me as their poster boy for suicide prevention, sadly, there isn't much I can do (even if I wanted to) after my death. As for the video of a guy who tried to commit suicide, either he used the wrong load or most likely aimed under the chin, which has a much greater chance of failure than in the mouth at a low angle and as far back as possible to hit (or destroy) the brainstem. Also, if aiming to high in the mouth can result in blowing off the frontal lobe (effectively lobotomizing the person) and still being alive. Usually people who botched the technique and died usually die from secondary causes such as blood loss, shock, or other internal injuries rather than just hitting the brainstem itself.