A young man sustains a gunshot wound to the base of his neck. He was shot point blank with a .38 caliber revolver. The entrance wound is above the left clavicle, below the level of the cricoid cartilage, and just lateral to the sternomastoid muscle. The exit wound is just above the spinous process of the right scapula. He has normal breath sounds on both sides, is awake and alert, is talking with a normal tone of voice, is neurologically intact, and is hemodynamically stable. Portable x-ray films of the neck and chest took in the emergency department showed some air in the tissues of the lower neck, but are otherwise non-diagnostic. Which of the following is the most appropriate next step in management?
A. Observation for several hours
B. CT scan of the lower neck and upper chest
C. Angiogram, esophagogram, esophagoscopy, and bronchoscopy prior to surgical exploration
D. Immediate surgical exploration of the lower neck through a collar incision
E. Immediate surgical exploration of the upper chest through a median sternotomy