If there's "nothing" outside, where does the air come from (and everything else)?!

Like water, electricity and even gas for cooking? And why is it eventually disappearing (flickering lights)? Makes no sense whatsoever. They should long have suffocated or died from CO poisoning.

Of course it's meant as a parable for society or the world in general and I kind of like and appreciate the idea... and it'd be probably quite accurate as it's depicted - but I can suspend disbelief only so far - they should be in just total darkness and run out of water, food and most importantly air soon and die in a matter of weeks at the most!