I wrote "His therapy is in the doctor's office", since "doctor's office" is precisely what "Praxis" means in this context, and the system told me I was wrong. Sure, let's always go for literal translation, who cares that the word "practice" in English in never used to denote "doctor's office".
Don't rely on Duo's meanings too much! With any translation, I think it is as important to understand the general sense of a sentence, or how one would try to say the same thing in another language, as it is to do a word-for-word translation. Sometimes, with idiomatic expressions, word-for-word simply does not give the sense. "Es tut mir leid" is one example; how does "it does to me harm" = "I'm sorry!" The articles in the "Immersion" tab are hard in some ways, but they do give a chance to translate in a full context, so some of these points are clearer.