Bob replies to topic two and starts to segue to topic three.
Carol has something important to say about topic one.
What is Carol supposed to do? Let the entire chain play out, then transition back to topic one when there's an opening? I know people can be bitter about interruption, but in my experience you get a prompt and decisive smackdown for trying to backtrack, especially when pressed for time. It seems important to get your point in while it's relevant. Interruption of the form, "hey, before we move on, can we talk about X" seems to be the way do that.
How would you handle this situation?
I'm especially interested in this, because interruption and other conversational "traffic control" flow much less naturally on international video conferences, and our remote meetings tend to be stressful and chaotic messes. Short of a formal, parliamentarian moderator, it's not clear how to make these better.