My camera stays on if I push the rear window defroster button 3-4 times quickly. It stays on until you shut the car off or hit the defrost button again. I use it at the track since the rear mirror in the GT3 is worthless. Not sure if it works the same on the .2 but it does for Nav TV which uses Porsche PCM programming, so unless they changed it in the .2, it should work.

Its not going to work. The NavTV module sits on (monitors) the Can Bus and sees the button getting pushed and sends the signal to turn on the video to the pcm.
Also the 991.2 has a different PCM. Maybe somebody will figure out a video in motion module and release it.