Possible Clues:

• Refuse to be disheartened by inspector's sorrow
• “Shouldn’t have bought that” feeling
• Deep regret about titbit left out
• Shame about son going inside again
• Deep regret as vibrations not leading to ecstasy
• Pity he's left here gloomy, having lost second round
• Sorry state
• Regret referring to signalling code
• Buyer's ___
• Deep feeling of regret