Possible Clues:

• Defensive fieldwork
• Engineers feel uncertain about temporary defence work
• Start worrying again about fieldwork
• Again suspect inner last retreat
• Where there's about nothing that's uncertain for the defence
• Temporary or outward fortification
• Yet again, be unsure of defensive work
• Have fresh uncertainty about fieldwork
• Defence for revolutionary, nothing but revolutionary
• Defensive position taken — concerned over lack of conviction