Well, it's not just "Five Autopsies" -- it's that in combination with what she says to Chaz in one of the "vigil" vignettes. That bit about knowing that if she ever developed an anomalous ability, they'd lock her up in Idlewood and never, ever let her go. I have the impression that she considers Idlewood to be a fate worse than death, and since we now know that she has killed in the past... I wonder if that "accidental" nick to the blood vessel was a little less accident and a little more what she would think of as a mercy killing. Which would make the wording of her final report both honest -- she knows she could have done it differently, and takes full responsibility -- and a bit of misdirection.
I'm not arguing that this has to be true, only that it's a plausible alternate interpretation, and one which I now see as in keeping with Frost's character as it has been revealed to us.
That was pretty much my interpretation from the get-go.