So I've listened to the exit international podcast and takeaways for me:
1. Kenny "if he had cooperated - could have had a peaceful and reliable death", meaning following a few instuctions Dr. N wishes he'd given Kenny, summarized as: dont hold breath, fully exhaled once n2 is on, and ensure the next couple breaths are deepest possible to fall unconscious normally & die within 5 minutes.
2. Dr. N said it might have looked scary but the "writhing" or any struggling they watched as he fell unconscious and died were likely typical death spasms.
3. Kenny still died while unconscious he just took longer to fall asleep first because he held his breath.
4. Dr. tried on the mask and felt it was a secure seal, but could possibly become dislodged.
5. Kenny had a beard and didn't cooperate in the process, spasmsed/ appeared to struggle to some onlookers, yet seal maintained for death while unconscious.
So, seems like one can mitigate risks with SCBA like possibly appears GasMonkey, rigbone, joeschmo (others?) chose if done diligently, i.e.:
1. Proper mask fit and donning (following manufacturer guide)
2. This includes shaving face and dealing with hair if longer.
3. Use positive pressure because designed to keep out outside atmosphere (any o2) and protect firefighters even in heavy exhertion or when falling unconscious from any external atmos entering (as long as you have gas).
4. Apply the rest of the inert gas best practices like proper parts & fitting, strapping in, strapping tank, practicing.
5. Practice, practice, practice - donning mask, breathing, the whole thing with a scba o2 tank safely.
Mega credit to:
Thread 'GasMonkey Setup [Nitrogen SCBA]'
https://sanctioned-suicide.net/threads/gasmonkey-setup-nitrogen-scba.115434/
Thread 'Inert gas setups gallery. Show your setup'
https://sanctioned-suicide.net/threads/inert-gas-setups-gallery-show-your-setup.115461/
Thread 'Exit bag and inert gas megathread'
https://sanctioned-suicide.net/threads/exit-bag-and-inert-gas-megathread.8393/
Thread 'Inert Gas Cylinder & Regulator, General Refresher Summary:'
https://sanctioned-suicide.net/threads/inert-gas-cylinder-regulator-general-refresher-summary.30657/