What's the deal with the sniper girl?

I don't get her deal and the whole subplot involving her. Here's what I'm confused about:

1) She's a NoKor escapee looking for her kid. She makes sure people are killed because? Is it so they don't suffer and die a slow death? But she kills people anyway, so whats with that ethos?

2) Then in episode 2/3, we find out that she knows the square SG staff guy 3 years back. So she's been the sniper (triangle SG staff) for 3 years now? What's the whole revealing of their relationship for?

3) She backed off after the two guys threatened to harass her and reveal her secret. What secret? That she's a NoKor escapee? Pretty sure whoever thought up this whole squid game wouldnt bat an eye that a someone from NoKor works for them.

4) Lastly, the people who harvest organs, they're a separate thing from SG right? Even if the person was shot twice, surely they can still harvest organs right? Why can they only harvest organs from people on the brink of death?