Possible Clues:

• See 12
• Wild otter round old city in distress
• Anguish gave you lesson we hear
• Infliction of great suffering
• The Geneva Conventions prohibit it
• Using wrong remedy with splitting head -- that's purgatory
• Unbearable suspense, say
• Did race around inverted groove cause extreme discomfort?
• Wrong treatment — not the first to cause extreme suffering
• Agonising pain