answer: #Person2# tells #Person1# the subway is the cheapest way to get to #Person1#'s destination and directs #Person1# to the station.
documents: #Person1#: what's the cheapest way to go there?
  #Person2#: By subway.
  #Person1#: Oh, is that right? Is there a subway station near here?
  #Person2#: Yes. There's one on the other side of the building.
  #Person1#: Good. Can I walk through this building?
  #Person2#: I'm afraid you can't. you'Ve to go out there and walk around.
  #Person1#: I see. Thank you.