Well, just my 2 cents, but have you heard of the Heaven's Gate cult? It was back in March 1997. You can Google this to find out more, including photos. But in short, 39 members of this "doomsday" cult committed mass suicide by taking phenobarbital mixed with apple sauce or pudding and washing it down with vodka with plastic bags secured over their heads.
As you stated, phenobarbital should not be confused with pentobarbital (aka: N). Phenobarbital is a much slower, longer-acting drug. In my humble opinion, chances are it was NOT the drug that killed them, but rather the drug that caused them to go into a very deep sleep and with the plastic bags over their heads, they died painlessly and peacefully of hypoxia (lack of oxygen to the brain, which would basically be the result of taking N too, by the way). By being in this deep sleep, the drug effectively turned off any survival instinct such as the Hypercapnic Alarm Response that would kick in otherwise to remove the bag when the build-up of CO2 in the bag (and blood) got too high. This allowed everyone to die peacefully in their sleep, likely never being aware that they were dying. Much like being under general anesthesia for surgery. In fact, it was reported that the police who were first on the scene said everyone looked to be sleeping. In other words, no signs of panic or fear, or contorted facial expressions, or anything like that. Just a sense of gentle slumber. The evidence seems to suggest it was both peaceful and reliable. A 100% success rate as all 39 died, regardless of age, gender (18 men, 21 women), weight, and overall health condition. The ages ranged between 26 and 72.
So if you can get Pheno (along with your favorite alcoholic beverage and make a plastic "exit" bag) you're good to go at a time of your choosing.
