I think I know what you are trying to do and if I am right it's simpler than it sounds.
Try this. I am assuming that audio in track 1 is not linked to the video.
Highlight the lower video track and go to the very first frame and place the scrubber there. Now without moving the scrubber highlight the top track and when you have done that select split.
Go back and highlight the lower video again and go to the very last frame and place the scrubber there. Now without moving the scrubber again highlight the top track. When this is done select split.
With the two splits in place highlight the top track and delete that section (delete and leave gap)
Go back to the lower track, highlight it and drag it up to the space you created.
Now you can add your transitions as necessary.
I hope this is correct
Panny TM10, GH2, GH4,