Senior Airman Kara Nicholas and 2nd Lt. Tomas Chavez check the vital signs of an incoming patient during Exercise Vigilant Guard March 25 in Camp Santiago, Puerto Rico. Airman Nicholas is a medic, and Lieutenant Chavez is a flight surgeon candidate. Both are from the 161st Air Refueling Wing from the Arizona National Guard. (U.S. Army photo/Staff Sgt. S. Patrick McCollum)