There is no resistance anywhere within the vacuum of the combustion chamber, therefore the entire chamber is the path of least resistance.
Why do you keep pretending that the chamber is not open to the vacuum?
It is, & therefore the gas will leave it by the path of least resistance, doing no work on the way.
Gases do not follow the path of least resistance.
When expanding into an area of lower pressure they do.
Which is what we're talking about.
the natural laws governing behaviour is fluids means that the particles behaving randomly will collectively tend to try and fill whatever container or area they are in
Particles that behave both randomly AND collectively?
Whatever; the 'container' or 'area' that a 'spayze-rokkit' is in, is the practically-infinite vacuum of 'space' itself.
So THAT'S what the gases from a 'rokkit-ennjyn' will be trying to fill.
Which is why they would all leave your silly 'combustion chamber' immediately...
By the path of least resistance.
Lastly, I will indeed LOL!!! at this:
Im sure Papa will just LOL at this as he does have a clue how real matter behaves but there you go.
Forgot to include the word 'not', Walt?
Bit of a Freudian slip there?
Toodle-pip!