Possible Clues:

• One runs into the sea? What nonsense - only in pantomime
• Participant in (and curtailer of) seaside show
• Pantomime character, one featured in bad report
• Single lapse admitted by dope, a one-time entertainer
• Comic character in whiteface
• Metal piece in locks drawn back up
• Clown has to run right back after confusion
• Clown makes brief mistake, getting into depression
• Male character from French pantomime
• I make a mistake filling receptacle for clown