From "Doctor Who: Daleks in Manhattan (#3.4)"
[the Doctor, Martha, Frank, and Solomon have volunteered to work for Mr. Diagoras, and they have entered the sewer
Turn left. Go about a half a mile. Follow Tunnel #273. The fall is right in front of you. You can't miss it.
And when do we get our dollar?
When you come back up.
And if we don't come back up?
Then I've got no one to pay.
Don't worry, we'll be back.
Let's hope so.