Your first 3 letters are correct. It's 2 letters for "this writer" reversed/returned then a 3 letter word for "work" around 8 - definition is "exploit".
I have the letters i, n, r and one other. The anagram solver on this website doesn't come up with anything Japanese or medical. Is my r wrong, perhaps. I wondered if the men were in the army they might be Royal Engineers or Royal Artillery.