Used to describe someone who is too preoccupied with the task at hand to notice potential obstacles and hazards.
Comes from the response of Jack Phillips, senior wireless officer on the RMS
Titanic, to a message from Cyril Evans, wireless officer for the SS Californian, which was meant to notify him of
ice dangers in the waters the
Titanic was passing through. Phillips -- who was busy relaying a backlog of messages from the as-yet-intact
Titanic's passengers through the wireless center at Cape Race, Newfoundland -- responded to the loud interruption with the phrase, "Shut up; I'm working Cape Race!" The Titanic struck and iceberg and sank