The concept of quantum suicide is important to the show. Just search it and you'll see why. A clue to this may appear in a scene in "The Glass Ballerina."
Belowdecks on the boat:
SUN: Stop; or I'll shoot.
COLLEEN: No you won't, Sun. I know you, Sun-Hwa Kwon; and I know you're not a killer. But despite what you may think, I'm not the enemy. We are not the enemy. But if you shoot me, that's exactly what we'll become. [she moves toward Sun]
SUN: Stop! I will -- I'll shoot you.
She then shoots Colleen. Do the Others become the enemy? Not officially. But Tom Friendly goes on to get shot. And Sun-Hwa Kwon knew that, since there were five others above them, shooting Colleen might have effectively been suicide. Kwon-Tom suicide. Get it?
I know, I know.