Risky. It takes a large, heavy, high current switch and if it fails, your Phantom falls out of the sky. Some have used jumpers made from XT60 connectors. You can wire a female connector in series with the main power wire and mount it through the body. Then you make up a male connector with a loop of wire connecting the two terminals.
Now you can insert the battery, plug it in, close the battery door then plug in the jumper externally when you are ready to power up.