Yes, precise circumstances matter.

For nitrogen asphyxiation in general, you do not have to be calm and cooperative for it to be painless, any more than you do so to stand in a room or sit in a chair.

As to the specific setup that the government chose, I can't vouch for that.

It doesn't mean thousands of litres per second to do it properly. A mask or helmet could be considered a poor tool for the job, though, because they are easier to fight/struggle with, and the person could hurt themselves in the process of that.

You need the normal level of air replacement for any given volume with a human in it, but you need to be using nitrogen as the source of air replacement. If you want to speed the process up, you could do 1x space volume/minute for a couple minutes, then drop it down to a normal rate of replacement.

Choosing a larger volume will not make it painful, but it will make it slower unless you increase the flow. But slower is not bad, per se, except that since it's an execution, faster is possibly more merciful (depending on the person's preference) because the person has less time to sit there and contemplate the fact of their death.

The suicide pods are pretty much the ideal balance of space taken. For an execution, perhaps a small room with a chair, and a somewhat faster nitrogen replacement rate (like, 60 volumes/h for the first two minutes, then 5 volumes/h after that).

But that's not a problem with nitrogen asphyxiation, that's stupid human implementation.

Ah. Well, if nitrogen asphyxiation is done right (a proper mask, or better, total immersion), cooperation is only necessary for the painlessness in the same sense that walking down a hallway or sitting in a chair requires your cooperation - if you smash your head against a wall, or pick up a chair and smash it and hurt yourself in the process, for example, it's not painless.

As far as a person's struggle to live - yeah, no shame in fighting for it.

I think that if you're a robot boop capable of enough complexity (including having a tendency towards dynamically stable emotive field states), and can interface with a body and society well enough to remain comparatively indistinguishable from a human, that makes you human, right? beep anyways, time is relative, right?

Then that's not simply killing him with nitrogen gas. But the better method is:

• A mostly enclosed cask with one exit, just large enough to prevent pressure buildup (vented to the exterior, since we probably don't want the whole room to be the same thing)
• solid nitrogen flow in

..that is all. If they're fucking it up, it's on them.

..that is all.

But also, even when completely unconscious, complex living things with a central nervous system (including people) tend to flop when they die.

No, they don't need to cooperate. If you struggle and thrash, no matter how you die, you'll endure the struggle and thrashing.

Yeah. The suicide pods are a good example. There's enough space in them that the person won't experience CO2 buildup in the short amount of time it takes.

Yeah. This is the thing.

Yeah. Pretty fucked system.

Fair.

Unless they are pressurizing the space the guy is in, nitrogen will just make you black out, without suffering (other than the human knowledge that you are about to die, but that exists with all methods).

You have no idea what you are talking about.

With nitrogen, you are literally be breathing out your oxygen. No, a rope is not faster. No, a rope is not more humane.

Nah. I know what happens. I've experienced asphyxia.

I don't have problems with murderers being killed. I just don't have faith in the system to prevent false positives.

No. Perhaps that they are doing it is horrifying, but the way is very humane. It is literally getting loopy and falling asleep, over a very short time period.

No. With the notable exception of rodents, animals generally can't detect oxygen deficiency directly (though they may get loopy).

Nitrogen asphyxiation basically makes you loopy, then unconscious, then dead. It's experientially equivalent to exposure to normal air at extremely high altitudes. Military pilots are often exposed to this (in a controlled manner) precisely because it's so hard to recognize, and doesn't induce fear. Like, epic levels of hard to recognize, as in "Hey Bob, it's time to put your mask back on to keep you from dying!" Bob: snickers and clearly thinks this is a great joke, until the person straps his mask back on, and he realizes how serious the situation is

You can make a trough for a (non-starved) pig that constantly releases nitrogen gas (which it breathes as it's eating). The pig puts his head in the trough to eat, then passes out from lack of oxygen (this pulling it's snout out of the trough), then is like "what was I doing? Oh look, food.." ..and goes right back to it, passing out again.

This is completely different from the reaction to carbon dioxide asphyxiation, which the body has sensors for, and induces all kinds of panic. Try the same trough experiment with a pig using carbon dioxide, and it will stay the fuck away from the evil trough of death.

They can kill an animal (including a mammal) if they become entangled and give up out of suffering, though.

This is pretty rare, but can happen.

It's virtually zero risk to a human, though, who can cognize things like getting their hand disentangled from a string (even in a panic situation), or to most mammals, which tend to jerk backwards on contact.

Oh. Here's your fix:

A longish piece of green grass. Hold it by one end, then slide it on the fence wire like the grass was a violin bow, getting your fingers closer and closer to the fence. At some point you notice a pinging, or your fingers are touching the fence.

You can use this to gauge, very roughly, how powerful the charge is at that point.

Absolutely.