Anna and Ben
Maybe I missed this, but was there some sort of past relationship these two had? The people in the CIA mentioned a few times that she had to put aside the way she felt about him or something like that, and when they were on the train together you could sense that they had a past, and not just a working-relationship.
Obviously Ben's wife had passed away, but since he had only been living in Belgium with his daughter for a few months, I assumed that his wife didn't die that long before that. When would Anna and Ben have been romantically involved, if at all?