^ I think they're all really brave at various points in time. But yeah, later on Chloe proves to be the bravest based on what she goes through. Greer is brave, but it's easy for him to fall back on it because he's a marine. Chloe is a civilian with no training.
I'm re-watching the series again... and wow, it has grown on me. Each time I see something else, something new. These episodes are chocked full of so much material, both in terms of story and emotional interplay. And I'm afraid I'm also growing to like the characters even more, including Rush. This makes it all the tougher to deal with the absurdly short run of only 2 seasons.