Makes having an emergency escape option #1 (aka death by self) seem like a good idea... for those cases in which your days or minutes are numbered, and you know the exact number.... and you know how you are going to die, and it's not how you want to go. You don't wanna give your would-be murderer the satisfaction.

It could all boil down to whether you have enough time to grab the syringe and the poison and administer yourself a painless lethal injection. Research would have to be done to find some sort of poison that is both painless and lethal... and, if possible, also euphoria-producing.