Rather, we use the word "dumpling" to refer to several different kinds of food, not necessarily round. The kind of dumplings I was raised with were just clumps of dough boiled in chicken broth. But there are also things like apple dumplings, which are fruit wrapped in pastry. Asian dumplings are basically similar to ravioli, which are also considered a form of dumpling, though I never heard that term used for ravioli growing up. I always took the etymology to be that they were small items cooked by dumping them in water, oil, or broth, but the dictionary says the "dump" part is more likely a variation on "lump." But even with subtitles, there are still going to be details changed in the translation, and ideas that go unexplained. (Although I once saw a fansub of Dairanger that included the occasional annotation explaining cultural references.) For a simple example, in Shin Godzilla (at least the DVD edition), when the police board the abandoned boat at the beginning, they say Sumimasen, meaning "Excuse me" or "Sorry" (for the intrusion), but the subtitles say "Hello?" because that's what an English speaker would expect someone to say in that situation. The ultra-politeness of Japanese interaction tends to get downplayed in subtitles because it's not a part of American culture.
I didn't translate the books, I was working with a raw translation that was done for CBS's approval and which was done with little regard for English grammatical structure. My job wasn't to translate, but to edit the translation into something that reads like it's in English instead of translated German. In particular I tried to make the voices of the characters distinctive and appropriate (and in the case of established characters who appear, accurate). And some idioms did not translate well and I had to fix those.
I read the German originals and listened to the audiobooks recently. I found PROM to be a gem that stands on par with current TrekLit. Very curious to see that iteration of Trek in English written form. And I'm hoping for sequels.
They both seem to be referring to the same idiom. The English version is a little less clear in isolation because it's usually phased as "to fight fire with fire," rather than "to [use] fire against fire." Just having the last part can make it seem the fires are companions rather than conflicting, but they probably figured English-speaking readers would recognize the truism and thought "against" would sound like, well, someone speaking as a second language.
Also in the UK, there is no eBook version listed at Amazon. In the US, the eBook is $8.99 and the MMPB is $7.99. So in either case, this is BS.