Even though the game cameras tell you only who is out there, they also where they are trying to break in. Additionally, most predators I deal with visit multiple times before attempting to take a chicken as generally there for something else first.
I have used baby monitors but you need to respond when the sounds of alarm are made. After doing some learning since, I suggest adding a low power night light inside coop to make so birds can see their assailant. That will give more time to wake you up.
Harden you coop as well and consider...