Somebody seems to be reading Conan...also, are you sure it's legal to kinda just screenshot that thing and paste it here? Yet again, it's for analysis purposes, so...
He's investigating them by tailing them. It is pointless for him to try to tail somebody by moving around in places where you already know the target isn't there.
It would be like losing your keys in the garage and your friends suggesting you look for them in the kitchen.
Always give weight to common sense and situational clues when you hit problems like this; it will help you see your way through grammar/vocabulary misunderstandings.
2)
When used with affirmative, でもない and ではない have different meanings, as in そうではない vs そうでもない. However, "negative + でもない" is almost the same as ではない in meaning (e.g. わからないでもない vs わからないではない). ばっかり persforms as a partial negation, so いいことばっかりでもない and いいことばっかりではない are almost the same.
The English translation for わけではない and わけでもない could be the same but there is a slight nuance difference.
I am not sure if I can answer this in the comment section but,
1) わけではない denies stronger than わけでもない
A) そういうわけではない That is not the reason / That is not the case /
B) そういうわけでもない Not exactly
わけでもない sounds more vague and it implies that could be a part of the reason.
2) However there are cases わけでもない emphasizes more than わけではない like "even"
C) 先生になるわけではない (It doesn't mean (this person) will become a teacher.)
D) 先生になるわけでもない ((This person) won't become "even" a teacher)
でも[接助係助]の意味 - 国語辞書 - goo辞書でも
[係助]《断定の助動詞「だ」の連用形+係助詞「も」から》名詞または名詞に準じる語、助詞に付く。
(not this meaning)1 物事の一部分を挙げて、他の場合はまして、ということを類推させる意を表す。…でさえ。「子供―できる」「昼前―気温が三〇度ある」
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(but this one)3 物事をはっきりと言わず、一例として挙げる意を表す。「けが―したら大変だ」「兄に―相談するか」
shes mad because rather than actually liking the girls who had the megami inside them he did it simply for the sake of capturing them rather than love. I think its better to interpret it like
怒られても = even if she ( its a girl in thsi case) gets mad at ( me)
仕方ない = it cant be helped
so all together its like," even if she gets mad it cant be helped" so the translation given is pretty spot on
But then I searched ても仕方ない and I found at least two "blogs" that were saying that it translates as "it is no use to...", "doing that is in vain", etc. But now the sentence doesn't make sense anymore ("It is no use to move around only here").
The problem is that, as I've written before in this thread, ても仕方ない all together means "it is no use to...".