Possible Clues:

• Sink, taking in water at the end
• River gets in low place, creating flood
• Audibly overwhelm (with "out")
• Render (doctor's confession?) inaudible
• Cause not to hear new promise being brought up
• Fuzz arresting ring leader in swamp
• Drench with dressing
• Be louder than, with 'out'
• Third of Tories wearing blue go under
• Flood having subsided with river contained