In order to slow down the ship in The Martian (or bring it closer to the MAV, I don't recall), the crew of the Hermes vent the entire ship – save for the cockpit – in the void. Then they rescue him.
Then... what? Even assuming they could seal the docking door again (side question: why did they have to blow it up, couldn't they just open it normally?), they don't have any air left. How did they survive the lengthy trip back in an oxygen-less ship? Did they all stay in the cockpit the entire time?