U.S. Army Sgt. Evan Lock, 30th Engineer Battalion diver, monitors the pressure inside a hyperbaric chamber, while 1st Sgt. Milton Prater, 30th Engineer Battalion master diver, communicates with the divers inside the chamber during a training course at Fort Eustis, Va., May 2, 2013. Divers went through a variety of scenarios including performing neurological exams and learning symptoms of common medical dive problems like "chest squeezes." (U.S. Air Force photo by Staff Sgt. Wesley Farnsworth/Released)