answer: The bad weather makes Joan and George cold and wet, so they want to go back home quickly.
documents: #Person1#: It's freezing cold out here, Joan! You said would be just a little chilly.
  #Person2#: Yes, I know, George. We should walk home faster to keep warm.
  #Person1#: Awe, and what is that?
  #Person2#: Oh, just a bit of thunder. Nothing to worry about.
  #Person1#: Just a bit of thunder? Nothing to worry about? Now it's pouring and I'm getting cold and wet.
  #Person2#: Emm, yeah, we should probably run now.