I don't understand: あなたに口を挟まれる事じゃない

Question

I have trouble with two lines that are closely tied together. The following is them in context. The lines in question are shown in bold.

A: 待ちなさい！B、あなたを確保します！

B: 邪魔よ……どきなさい。

A: あなたは今、bla bla bla, irrelevant anime bs 状態なの…… そんな状態で暴れて回っても、 なんにもならないんだから……

B: 何にもならないかどうかは、私が決めるわ。あなたに口を挟まれる事じゃない。

A: いいえ！口も挟めば手も出します！

The "irrelevant anime bs" is just me stripping the bit that explains B's situation in more detail, but that detail IMO would just lead us down the rabbit hole of explaining lore and like which is not the point here.

The following is my take on this segment:

A: Wait! B, I will arrest you!

B: You’re a nuisance…begone.

A: You are in a state of (irrelevant)… Because of that there is no point in getting violent, so…

B: I’ll be the one to decide whether or not there is any point. I won’t be interrupted by you.

A: Noo! I'll either interrupt you or fight you!

First of. For me it's strange that the verb 口を挟む is being used. As far as I can see it's used for interrupting someone's speech (like mouth is right there in the verb as object), while here from context B (which is suffering the interruption from A it seems) hasn't actually had her speech interupted. But more A is going to secure/arrest her and prevent her for going where she wants. And I don't really see in the definition of the verb it being used for this kind of thing.

Second thing is the 事じゃない which I'm not entirely sure what it's doing here. Is it, "it's not a situation where I'll suffer being interrupted", or general "I'm not/won't be interrupted by you" or something?

Due to the accumulated confusion, this makes the A's reply even more confusing to me. I know about the も～ば～も pattern that is used for and/or either/nor and such. So I guess she is saying she'll either interrupt/stop or fight her.

Answer 1

First, to address the the expression「（Xに)口を挟む」, you would be wrong to go on this first sense of 「挟む」: 「① 物を両側から押さえつける。また、二本の棒などで押さえて持つ」 and visualize this idiom as squeezing the lips of a talking individual tightly together, therefore temporarily depriving them of the ability of speaking ( = interrupt). Rather, the more relevant sense is the next one: 「②ある物の間やすき間に物を入れる」. Taken literally, the expression should mean "wedge (your) mouth into X", where the metonymical "mouth" is that of the interferer, not of the interfered (think the English idiom "stick your nose into X"). This idiom can be used with regard to interrupting someone's speech with your words as well as meddling in a matter that does not directly concern you. So the its use in this context is unexceptionable.

As for the second question, the the whole utterance is not a general statement but about the particular situation at hand. So the sentence may be translated into: "This is not a matter in which I have to suffer your meddling!" (Or more simply: "This is none of your business!" ).

Now, onto the last point, which I find a bit tricky because「手を出す」 has two meanings that are (it seems to me) applicable here: 「① 人や物事に自分から積極的にかかわりをもつ」 and 「② 暴力を振るう」.

In the case of the former, the phrase would be synonymous enough with 「口を挟む」 for the combination to be pleonastic, with 「手も出す」 only adding some rhetorical force, but not much in the way of new semantic content. ("Oh yes, I will stick in my nose, and my butt too!" )

In the case of the latter, A would be vowing to do physical kind of meddling, not just verbal. ("Oh, I will butt in, and I will fight you!") ... upon further consideration, I think I'm beginning to lean toward this interpretation.

Answer 2

What's interrupted is not her speech but her private affair. In this sense, it's more like "to claim something" rather than "to interrupt".