I think the idea was that she was conflicted about leaving her and didn't have the conviction to condemn her to death in quarantine. I think it's plausible that seeing a violent creature in the room made her feel like she should actively do something; locking her in there with a virus that may or may not infect her is one thing, abandoning her when she's getting attacked is another. It's one of the few scenes in the movie where you can say that the characters did something dumb for believable reasons.
But her running back in conflicted what she was doing 2 seconds prior. Again, they are aping Alien with Ripley and Dallas arguing on letting Kane back in. The issue is the characters don't have consistency with themselves, but what the plot needs. Where they will betray the very thing they were doing just prior.
They set her up as worrying on contamination, between asking what is happening, throwing the bags out, locking the door, etc. Her leaving her friend to die makes sense or even locking themselves in.
But then her running back in with a gun blasting is the exact opposite of what her character was set up doing prior.
I feel like this wouldn't be an issue, except they do it several times in the flick. Between dude who follows David, Ten and the ship, etc.
There comes a point, where you can't have the characters sacrifice their character for the plot/action sequence.
Hell, the battle with Ripley 3 goes out to do battle on the shuttle does not make a lick of sense. She is running scared the entire time. Now? She is swinging from the ship on a harness doing battle and control a giant fucking claw. There is nothing leading in this. There is no, I can use a power loader, or her taking charge, or her picking up a gun, etc. It just Give me a gun, let me go fight this thing that's killed fucking everyone in a ridiculously stylish way with no lead up.
Presumably they were relying on scans alone for the original planet they were going to colonize, though, right?
Yes, they were scans with the probability of the highest chance of success. Not that it was a sure bet. Simply, it had the best chance. No one was ever there.
Till they scanned the new planet, which exceeded those estimates. Where it would be an even better choice.
It's not like it was unfounded why they went there. Daniels was doubtful, because it was way too good to be true. Versus the Billy who thought it's worth checking out.
