Warning: very spoilery. (You can read my review here.)
“Humanity is already dead if they think sending us up here is the way to save it,” says Alana to Isaac, during one of her increasingly frequent revelations of what kind of person she really is.
“Killing is my drug,” she admits, as she tries to convince Isaac she and he are alike.
Yet it is Alana who represents the increasing deadness of society, trying to chip away at Isaac’s humanity. He represents the flawed but decent; she is amoral and feels no remorse, using whoever she thinks can unwittingly help her.
Never slow to blame Isaac when he hasn’t done anything – whether for attacking her or blowing up the ship – Alana, unable to accept life in the space colonies, also tells him she sees him as her ticket out of her situation.
She’s clearly a psychopath. Even before blowing up the spaceship we see a flashback of her shooting dead several of her drug dealers apparently because she didn’t like the drugs they were selling. She’s perfectly capable of face-to-face murder and large scale attacks.
Eventually she overplays her hand. Ground Control tells Isaac they have checked the video footage and know she blew up the ship; and Isaac becomes wise to the lengths she will go to save herself.

She’s simply a product of life back on Earth though: of the policies of the authorities back home, playing out via Ground Control (the proposed rescue isn’t happening, with many other victims drifting in space in their capsules) and through the media on Earth (Clara tells Isaac the Prime minister is offering pardons to those who make it home alive, though as Alana points out they’re sure to try to wriggle out of that).
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Isaac is still clinging on to what makes him human though: love and hope. Eva the assistant tells Isaac he has a 22% chance of making it back, and just a day until the air runs out, butClara pleads with him by phone to take that chance on life. She adds a 2044 joke on the end: she won’t tell him which way she bet on his survival until he’s back on Earth.
Alana attacks him when he tells her he wants to take the chance on getting back home, but he tasers her until she’s unconscious then straps them both into their beds with oxygen masks on. They re both conscious as they go through re-entry and she seems to be smiling under her mask.
What we really want to know is: do Isaac and Alana make it home against the odds? Well, we never find out.
The film ends as the tiny capsule tries to make it through re-entry, though it’s as much about a battle for what makes us human.