answer: #Person2#'s late because #Person2#'s watch stopped.
documents: #Person1#: Here you are at last! You're half an hour late, you know.
  #Person2#: I'm awfully sorry to have kept you waiting for so long.
  #Person1#: What happened?
  #Person2#: My watch stopped and I didn't know. I certainly need to buy a better one.