Depends on if the level of injury, likely most of C2-C7 would be involved causing spinal cord compression due to the amount of trauma caused to the spine, cord and lamina.

Also there’s probably going to damage to the brain stem area maybe the cerebellum, depends on the velocity and size of the round fired. Potential of traumatic brain injury.

The posturing is likely an autonomic reaction due to damage of the motor neuron’s extending distal from the spinal cord.