She is seeing the outcome of what will happen if she uses the shears and severs herself from her “Savior Emma side”
Yes, though this begs the question, which part of Emma–Savior or non Savior–do we see getting stabbed? Emma kills the Savior side of her (the one that is constantly shaking) and her “non Savior” side lives. Except then Emma realizes she needs to be the Savior, that it’s part of her identity and the second half of S6 is about re-Savior-ing Emma.
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"He was a lot of things to me" "The only conclusion was love"