Carol has to let it go. Worst thing to do is interrupt the current flow. She will come across as a "Barker" like she had sat there not listening to what Alice or Bob had to say and was just thinking about what she wanted to say about topic one the whole time.

Best thing to do is wait until the end and circle back with a question that leads into discussing topic one. Doing this you immediately relinquish control of the conversation, and when appropriate say your thoughts.

Otherwise, just let it go. Is it going to kill you to not say it?

I read a good summary once of analysing the thought process:

- Does this need to be said?

- Does this need to be said by me?

- Does this need to be said by me now?

Which are good questions to ask when interrupting the flow of a conversation.