Sgt. Phillips searched all approaching vehicles at the gate of the Air Force base where he was stationed. When Captain John Hansen arrived for his scheduled flight, he was subject to search as well despite being an officer (on account of the heightened threat level). The sergeant's efforts of inspecting the car did not uncover the presence of Mitch Anderson, an operative working for terrorist ringleader Habib Marwan.
Background information and notes
This character's name can be briefly seen on the name tag of his uniform.