Suicides occur at the intersection of extreme impulse, availability of lethal means, and states of intoxication which inhibit parts of the limbic system and amygdala that support life.
There is no such thing as survival instinct in the school of suicideology. There are eight scientific definitions of instinct, and it's unclear which is being invoked. There are instincts that can be acquired, instincts that are imagined, instincts that are physiological but not protective of life, acquired birth, not acquired at birth, conditioned, extinctable, non-extinctable.... etc. Survival is a theological idea which has no basis in science or suicideology. We are not goal oriented towards survival but towards the propagation of our genetic material. This was expressed in a recent paper.
The survival instinct which is assumed here is really just a combination of fears and inhibitory mechanisms to impulses. The fear of death, fear of the unknown, fear of failure, for those that are religious the fear of the afterlife. The only conceivable means of manipulating the brain into killing oneself conceivably and theoretically could be self-hypnosis, but only for the most suggestible. Additionally, repetition does and has been found to be a fear extinction effect as one modality by exposure. Off the top of my head, one modality could be playing a low probability game of Russian roulette only in close calls which are not exactly doable unless you're playing Russian roulette with a 1 in 100 revolver. Or taking 99 blank bullets plus 1 live round. Taking a bullet at random from a box and pulling the trigger. Eventually you'll hit that one in 100th shot, but that is one means of mitigating SI. The probability or quantity of blanks may be adjusted accordingly to one's tolerance.
The majority of suicides occur during an acute impulsive or altered mental state in combination with the lethal means on hand and under the influence of intoxicants. So it would be easy to overcome the prevailing definition of SI by having a CTB ready go kit handy for when an impulse comes and a bottle of Jack to inhibit the parts of the brain that would be protective to our bodies from perceived harms or injuries such as alcohol on tap for when an emotional state of carelessness or impulse strikes.
I will cite a paper shortly on the subject.