Which one is correct in what case?
I have found someone suggesting that you use "at" for organizations and "in" for fields or disciplines, e.g.,
I've got an internship at NATO, and he's got an internship at Red Hat, but she's going for an internship in engineering.
These are clear, but there are corner cases less clear to me. For instance, would you say:
- "I've got an internship at the department of psychiatry at a hospital in Boston"; or
- "I've got an internship in the department of psychiatry at a hospital in Boston"?
...since here we are speaking of a place, however the emphasis lies on the discipline. Or are both fine?