Possible Clues:

• Scram ... or a hint to solving 17-, 20-, 50- and 57-Across and 11- and 28-Down
• Begone - without the map?
• Stop pestering me!
• Go away and lose your way
• Understand, and see a way to beat it
• Require orientation?
• Might bad map readers beat it?
• Words before a disappearing act?
• 'Let's go, prepared, ahead of time?' 'Stop interfering!'
• "Scram!" ... and what the last words in the starred clues' answers often do