The dictionaries give many possibilities, and deciding which one to use in a particular context is not always easy even for a native English speaker. Sometimes none of the dictionary offerings is really suitable, which is why my thesaurus is so well-used. But the problem of scientific terminology is undoubtedly the most crucial one. But if your editor cannot rely on your terminology, then he or she must spend time verifying every unfamiliar term or sending out queries to other translators for help. When I am translating an article on an unfamiliar subject, I often need to look at both the current and reference literature in order to learn common usage.
Translators do make serious mistakes which unfortunately get published.
However, it might be safe if they are very well known internationally in the field and actually originated the theory, technique, or device under discussion. Experience is a real advantage, however. I do much less library research now than I did ten years ago, because I have already worked out so many problems of this sort through reading the related literature and have accumulated thousands of term cards. A very important way to avoid errors is to simply carefully proofread your finished translation. Compare each sentence with the Russian original.