The simple way would be to think of it in a similar manner to a downlight. The way downlights are installed these days is that the sparky installs a powerpoint in the roof near where the downlights are and they plug the downlights into the powerpoint in the roof.
You could get the same thing done for the outdoor camera. Get a powerpoint installed in the roof and put a small hole in the ceiling to run the cable to the camera.
Never be afraid to back yourself when trying new things, just always make sure you have 3 escape routes if things go wrong.
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