[null and void]

Just use an N2 chamber. The squash gets hypoxic and "Night, night".

I was thinking more along the lines of a fishbowl helmet. No point in wasting an entire room full of nitrogen.

[Peelod]

It's necessary to dilute the exhaled CO2 to atmosphere to avoid the suffocation anxiety that accompanies acidosis.

N2 is cheap. There probably a N2 generator at your corner auto repair shop.