- If we click on "Enhance", we can clearly hear the background conversation being held during the taping of Arthur's horrible rendition of "Danny Boy".
- The conversation was between Charlie and Nic. Nic reveals a big secret that he wishes to be kept secret.
- This further fuels my theory of Sarah and Nic having an affair. Nic accidentally spilled the beans in a moment of vulnerability and had to make sure Charlie stayed quiet.