masonrm

I'm looking to install cameras on either side of my 2 car garage door that has these columns on either side. it looks similar to this I installed a A/V box in the drywall on the inside of the garage, and I found sheet metal between the drywall of the inside of the garage and the back of that column. I'm not sure why it's there or if I should drill through it or not to run my cable. Friends / neighbors are stumped as well. I used my snake camera to look down into the wall and it seems the metal goes down a ways and is the width of the column, so it's not a simple bracket that I can go around. Any ideas? Pic of garage door and columns