MRCP2-3130

A 35-year-old man presented to the emergency department with complaints of intense neck pain after shooting at a rifle range. He subsequently experienced vertigo, nausea, and vomiting. A few hours later, he was discovered collapsed at home and brought to the hospital by ambulance. On arrival, his Glasgow Coma Scale (GCS) score was 10 out of 15. What is the most probable reason for his symptoms?