Possible Clues:

• Steep slope
• Protective embankment
• Steep artificial slope
• The side of a ditch beside a rampart
• In a (less conventional) sense, vehicle goes down slope
• Inner wall of a trench
• Steep embankment
• Cares about leading Penny onto slope
• Points to beef's sharp decline
• Slope beneath rampart - it needs to be removed from exercise after retreat