Life And Death

'She' would devour her and put her into a slumber. Being unconscious forever, how was that any different from death?

Enigma could choose to bring down Sia and 'Her' and let them all die together. But she didn't do that.

She was grateful to Sia for giving her the opportunity to live. When she just 'woke up', she was still weak.

Sia had plenty of chances to 'devour' her and put her to rest. She didn't do that. Perhaps because out of pity. Or maybe because of her loneliness. Sia let her live.

Just for that, Enigma couldn't let Sia die.

Moreover…

'He doesn't want her to die.'

Varian went from absolutely hating her to being neutral and even treating her somewhat normally.

The repulsion still remained, implying that his inner feelings weren't overcome yet.

But Enigma felt that she shouldn't cause him any more pain after wrecking his life. She didn't want to see him in pain.