Speaking of pressure, they could reduce pressure considerably to save on vehicle, suit and habitat structure.
Space suits usually use around 0.3 atm. Although the ISS uses SLP, so they probably want to keep things safer in the larger structures (dilution with N2 or Ar provides some cooling that keeps fire hazard lower than reduced pressure O2 -- let alone full pressure O2).
Speaking of structures, the bag-over-burst-hatch depiction only inflated to about, what, a foot of water column, if that? (Of course, it would've been easiest on set to just get a big powerful fan and point that at the patch.) That ~1.5m hatch would've had to actually bear about 5.4 tonnes of force*, minimum, and more likely 10-15. (Any guesses how much duct tape would be required?
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(*That is, tonne-force, i.e. 1000 kgf, as in, the accepted figure on Earth. Dang, kgf etc. would all be different units, following their colloquial definitions, on Mars, or the Moon.)
Curious how the book handled it; I expect it was simplified for the movie.
Tim