The moment when it all fell apart in episode 5 (contains spoilers)

So the English botanist has some sort of mental breakdown in his lab and decides to go out for a walk, too confused to realise that by opening the door he and eveyone else would get sucked outside. If his wife had not managed to close that other door then everyone else in the compound would have been sucked outside.

So why was there an outside door in the botany lab? And if there was a need for one surely there would be a fail safe airlock (with 2 doors, the outside door can only be opened when the inside door is locked)? Not only to prevent accidents but also to prevent sabotage and incidences (as in this episode) when one of the crew has a breakdown.

The deaths of the 7 crew members nearly caused the expedition to be abandoned, but surely, tragic though it was, the expedition would have carried on, the real life deaths of the Challenger space shuttle crew as well as a reported 11 other deaths in space did not put an end to space travel!

And whilst they were preparing for the return to earth (before the return was cancelled), some crew members went back to the ship that they arrived in to see about getting it ready, but how were they going to use that ship to get back to earth? Where would they get the fuel from? Did I miss something?