If I recall correctly, you will have to meditate in order to change the medallion's detection system.
''They say truth is the first casualty of war. But who defines what's true? Truth is just a matter of perspective. The duty of every soldier is to protect the innocent, and sometimes that means preserving the lie of good and evil, that war isn't just natural selection played out on a grand scale. The only truth I found is that the world we live in is a giant tinderbox. All it takes...is someone to light the match" - Captain Price