Its reliability is 100% but its peacefulness is 50%. Against SN, potassium cyanide needs stomach acid. So only thing which is needed is fasting, maybe more than 12hrs. And 2g potassium cyanide in water or in capsule. I've potassium cyanide too, but I preferred SN because of its peaceful.
Combining potassium cyanide with exit bag is my plan B.