Mad Dog Maddox by Louise Collins

Boredom, or as Maddox liked to think of it, the slow descent into madness. It droned in his head numbing all sensation. The mad dog of years ago no longer had his bite. His heart still thumped beneath his ribs, his lungs still expanded and lifted, but the empty chasm of boredom kept expanding. Even a betrayal didn’t stir him from his stupor. He knew what he had to do, but felt nothing.
Beethoven filled the car, vibrations the only stimulus to awaken Maddox’s comatose nerves. Ian had stolen something precious, something meaningful to Maddox and he had to die. One of the others could have handled it, but Maddox needed to be the one to dispatch the traitor. The dog needed to reclaim his bite.
The shot rang out, not a boom but a high pitched ping and he knew he’d hit the mark. He’d never missed.
But Ian kept on going, headlights of his car fading down the street.
Maddox stared at his hand on the gun, noting with a sense of bewilderment the tremor and the rush of pimples. He had missed. He never missed.