When you choose chat type: window, your private chat will open in individual draggable, resizeable windows.
Now you can start an exclusive webcam video chat inside that individual windows: you just need to check the option: “Private tab window has webcam” inside your chatadmin / config / webcam panel
Notice that this webcam is EXCLUSIVE to an user: other users will not be able to watch at you and also, you cannot open many individuals webcams at the same time.