The Law against killing a human being with magic isn't based on using the proper procedure to fulfill a set of written legal requirements, such as; reading a suspect their legal rights by mortal police in the U.S. is required by a specific Supreme Court ruling made in 1966. It's based on the idea that killing with magic twists the psyche of the person who does it. It sets them on the path to becoming a warlock. We saw this in Harry. Harry killed Justin in self defense and that came close to pushing him over the edge. So I find it difficult to believe the White Council only learned this a century and a half ago. They would have devised methods to avoid burning someone to death with magic. So there must be some other explanation.
I'm not saying they only "learned" it recently, any more than police only learned recently that bullets can kill people.
I'm saying they made a special exception for their law enforcement arm in consideration of the dangerous job they did, and the possible necessity of using deadly magic to keep their lives.
Luccio says the she "seen no evidence of magical defenses" in the four warlocks she spotted, and further states "an overwhelming attack might take them all at once." She does not say "kill them at once," though her language can certainly be interpreted that way. So perhaps she meant she could; very painfully, incapacitate them all at once, and then either arrest her suspect or if necessary kill him with her sword. I think it is either this explanation or Jim forgot the specifics of the law against killing with magic. So if it is the former I think Jim could have written it more clearly. Then again, there might be a third explanation.
More to the point, though, she doesn't factor their deaths into her thinking. I'm not looking at her reasons
for using a magic attack, but her reasons for
not doing so -- that being the danger of burning the place down, and the danger inherent in using her gifts in front of others. She does
not consider the consequences of killing the warlocks with her magic. Counting on magical fire to
only incapacitate and not kill is a little like "shooting to wound" -- at best, extremely unreliable and the moment you've pulled the trigger/set the fire, you've put things out of your own control.
And again, considering how central the laws of magic are to the setting in general and the first law to Harry in particular, I
seriously doubt he'd "forget" the "details" of "do not kill with magic," especially since he's clarified a few times what counts and what doesn't. It's like Tolkien forgetting that the Ring tempts people.
In the introduction to the story Jim said he wanted to focus on the young hotheads of a given era in the Dresdenverse verse. So young Anastasia Luccio must fall into that category. Unless Jim gives us information to the contrary, that still puts her a long way from Harry's thinking in Storm Front when he was considering burning down the shadowman's home and everyone inside it. Luccio's thinking was more analytical, more dispassionate. So, we could take the extreme position that this is a clue that Anastasia is really a much darker character than we realize.
I took it more that even as a "hothead," she's still not as hot as Harry. Also, Harry's thinking in Storm Front is half subconscious, borne out of his own Black Magic taint. Here, Luccio is just thinking as she does her job.
Perhaps she is a member of Harry's Black Council. She wasn't Peabody's victim, she was his collaborator and the plan all along was to set up Morgan for La Fortier's death The mental damage the Gatekeeper detected in Luccio she did to herself. It could have been done by accident in order to convince Morgan that someone else was manipulating her or Luccio might have realized that she might need an explanation or alibi should things go wrong, so she decided to let Peabody use some magic on her to better help the illusion her relationship with Harry was based on her real feelings and desires, and provide her with an alibi should she need one. I'm not saying I buy this WAG myself, but it's more satisfying then saying Jim's use of language was sloppy.
That doesn't wash with the Gatekeeper and Molly finding evidence of Luccio being tampered with.
Added to all that, Harry himself has said the Council gives leeway with self defense and specifically with dealing with Warlocks as far as the First Law goes. I'm more inclined to think we're seeing a version of that than that Jim "forgot" a central, important part of his own setting.
