Yes, she is pretty cool and great. Yes, I was drink some coffee (and cigarettes obviously) and I thought - may be that idle guard doesn't turn around because I should need to kill everyone like a trigger to the others guards. I thought like a murder, "I shall keep some guards alive because they aren't bother me, and I would have some sort of alibis to decrease my guilt in case of law court. if you know what I mean. hahahaha This is might be a second ending. keep it in mind, - murder all and you are single guilt; but murder a lot of them left some alive, your guilt could be reduced, at least in Brazil. The guards who was in murderous scene was the main suspect and you, oh you could show yourself like a victim, a little smart girl who wants survive.
Of course, as in dishonored, the fewer you kill, the better, but the problem is that the story was already scripted and Zoe is supposed to kill everyone in that part, it's because of the plot, she can't have another ending because otherwise she wouldn't open DM 3 hahahah, different endings implied different sequels