Cpl. Nenyi Nyen, a fire team leader with 1st Platoon, Company L, 3rd Battalion, 25th Marine Regiment posts security during a cordon and knock exercise at K2 Combat Town, Camp Pendleton, Calif. May 28. The Marines conducted a cordon and knock exercise in preparation for their upcoming deployment to Afghanistan later this year. - Cpl. Nenyi Nyen, a fire team leader with 1st Platoon, Company L, 3rd Battalion, 25th Marine Regiment posts security during a cordon and knock exercise at K2 Combat Town, Camp Pendleton, Calif. May 28. The Marines conducted a cordon and knock exercise in preparation for their upcoming deployment to Afghanistan later this year.