The character becomes hypersensitive to sounds and changes in air-pressure, so sensitive that he gains a limited kind of precognition. He can’t be surprised [CofD 88] and applies his Defense against Firearms attacks.
Drawback: People move constantly in a hundred small ways, every twitch, every breath could be a threat and the character can’t keep up with all of them. When in the same room with more people than their Composure the character starts to get panicky. After Resolve minutes he takes the Terrified Condition, with other people as the source of his fear. Other creatures of the Darkness don’t trigger this blind panic and are never the source of the Condition (though objectively they’re far more likely to be dangerous to the character!)