Yeah, I was a bit confused there too, because, on the one hand, she admits to Ruby that she doesn't care at all what happened to Emmett, but then she goes and reenacts it. I think there are two possible ways to go with it, but they both might be the same thing as well. One, she wants to test if her invulnerability spells works and/or how it works, two, she actually really does love/care for Ruby, so she wants (in a sense) to care about Emmett, wants to care as Ruby does, even though she did throw that back into Ruby's face with the cynical take on why Ruby came back to her/William.

Perhaps, in the sort of end, Christina doesn't want to care because it isn't expedient, but she does want to understand, because she love/cares for Ruby, even if she won't let herself do so fully because she feels tied, or bound, to her ambition(s). I don't know, but I think it is something along those lines.

Yes that was definitely quite an odd scene. As others have said I assume for her to test the invulnerability spell - I guess that was a pretty thorough test of someone being killed in many different ways and it not finishing her off! There is definitely a lack of humanity around Christina, a detachment that you sometimes get portrayed as scientists in films who are doing horrible experiments on their subjects etc. I'm not sure whether that is what they trying to portray or like H says they are showing that she is trying to care.
There is also the possibility that it is ultimately showing how the child died (I guess that scene would have been beyond the pale to actually show) and it adds to the theme of subjugation which runs through the show.

Fav character along with Hippolyta. The final scene with her was odd I agree - see what happens

I do enjoy a good Demon of Protection - now what else will it/ can it do - will they dare use it.

9 tailed Fox spirit - new take on that myth