Ok heres my theory:
This is related to demons. Everyone has those thoughts in their head that tell them things they don't want to hear. Lies (maybe even truth in them), self-hat, jealousy, and misconceptions. After pondering on it with how she kills her clones (demons), I truly believe its like this quote I seen
"We all have demons. We try to drown them but they'll swim back up. You'll have to learn to tame them or they'll them tame you"
But instead of her drowning them, she is constantly murdering them... but obviously they keep coming back.
It does have a deep meaning, but there is also a simple cover to the meaning. That we all have those voices in our heads that make us more miserable and unsure then what we should be.... I'll come back with more when I contemplate some more ha. Let me know your thoughts. ^.^