Yeah, I’m pretty sure* they took a method that was supposed to give a clean painless death and deliberately implemented it in a way that would cause agony.

Edit: after further reading about this, there are other possible mechanisms that could have lead to that first one being in agony, so it is possible that the nitrogen asphyxiation method was approached and implemented in good faith while still causing agony. Though I’d say continuing to use it despite how the first one went does bring that good faith into question plus the possibility of good faith doesn’t imply it wasn’t in bad faith, but I no longer stand by that “pretty sure” I originally stated above.