The situation is that the main characters, a group of mostly teenagers who are surviving a zombie apocalypse, are walking through a neighbourhood where some of them used to live.
The character with the sword, Saeko, says
〈奴ら〉になっているのは君たちの隣人だ……. Meaning, "The people in this area that have turned into zombies are your neighbours..." (Not an exact translation, of course - I'm adding more context to help clarify the situation.) She's saying that she should go forward and be in a position to kill zombies because if the other team members recognize a zombie as someone they used to know, then they might hesitate.
Another character, Takashi, who is one of the people who used to live in the area responds
……家族をやれるか／ということですか／必要ならきっとーー. "You mean if we have to kill someone from our family? If we have to we'll definitely..."
Saeko cuts him off and says
That's where I get a little bit lost on the nuance. I get that the baseline of what she's saying is, "friends and family are different", which I think can be extrapolated more specifically to, "killing family and killing friends is different."
But, because it ends in
よ, which to me seems like an assertion, but the sentence also ends with a question mark, I'm not sure if it's a rhetorical question as a statement or a sincere question. As a response, Takeshi thinks to a moment when he had to kill a friend, but since I'm not sure of her statement, I'm not sure of the meaning of his reaction.
Is she saying "Killing family and killing friends is different, don't you agree?" Meaning that of course, it's different, so you shouldn't think you can just because you had to kill your friend before. Takeshi was able to actually kill his friend, but maybe Saeko is saying killing family is harder.
Maybe she's asking "Is killing friends and killing family different?" leaving it open for Takeshi to consider the difference. Maybe Takeshi then just reflects on how hard it was to kill his friend, even though he eventually did it, and realizes that killing his family will be a challenge.
Or maybe she's saying "What's so different about killing friends and killing family?" Meaning both are difficult. Takeshi then remembers killing his friend, and this steels his resolve to face up to killing people he might remember.
Or maybe it's something else entirely. Is what Saeko is saying a genuine question? What exactly is the subtext of it?
Also, her words all have dots beside them, indicating emphasis (my understanding of these kinds of dots is that they're like using italics in English). Is the emphasis for the benefit of the character Takeshi, or for the reader? And how does the emphasis impact the meaning?