The outer door's mechanism was broken... it was probably trying to close, but couldn't
That's the joy of the airlock system, though; one doesn't open until the other IS closed, not just TRYING to close. If the inner door can't close, the outer door won't start to open.
And here's the fun question to go with that: WHY is the door stuck halfway open/closed? Why is the shuttle door open as well? If this thing was unmanned, and no one came aboard, both of those doors should be shut, as that's how you would have sent it off. Someone's been here...
On the shuttle it seemed the only door control was on the inside of the shuttle. If that closes when your out and about on the ship you can't get back into the shuttle...which does seem insane. As for the other door, no idea why it won't always be closed unless someone is using it.
Can't remember it exactly put did the door just need someone to press a button? If so they could have used a Kino and run it into the panel and close the door that way. Then in the future they can just use that kino to open the door again.