Staff Sgt. Brandon Dotson, completes the 40th Marine Corps Marathon Oct. 25 in Arlington, Va. The veteran served 12 years of active duty service in the Marine Corps. This was the third marathon he completed in 15 days. - Staff Sgt. Brandon Dotson, completes the 40th Marine Corps Marathon Oct. 25 in Arlington, Va. The veteran served 12 years of active duty service in the Marine Corps. This was the third marathon he completed in 15 days.