"Okay, let me just video call you because I also need to show you something" and then the scammer hung up and was to never be seen again.
The scammer starts a video call with the person they want to impersonate and record it. When that person takes the call, the scammer doesn't say anything. This creates a 5-10 seconds video of the person looking at the camera waiting for the scammer to say something, until they get fed up and hung up.
The scammer then calls the victim. They offer a video call as verification straight away, and they play that short video.