Possible Clues:

• Talked on and on
• Buzzed
• Went on and on
• DRD, by the sound of it?
• Talked in a monotone
• Talked in a monotonous tone
• What the doctor did, by the sound of it, with a 21 across five hundred
• Went on and on and ...
• Went on and on ...
• Buzzed by unmanned aircraft and died