No one has yet come up with a reliable way to stifle Survival Instinct. Even more than N, that is the Grail of suicide.
There is a way past SI for each of us, but as near as I can tell it's specific to each individual, and it is a moving target. What you're sure will work one day turns out to be worthless the next. What your comrades in misery suggest must be a perfect block to SI --alcohol, drugs, music, meditation-- turns out to be a complete bust. Only a successful attempt will tell you what really works.
I've had six failed attempts in the past 12 months; all SI, all despite a peaceful, reliable method (eb/N2). It's a bitch.