Special tactics officer candidates carry a Zodiac boat to the shore during a selection at Hurlburt Field, Fla., Oct. 21, 2014. Special tactics career field training pipelines are some of the most physically and psychologically challenging in the Air Force. To ensure the correct individuals are on the battlefield, a group of special tactics Airmen weed out the cross-training candidates who don’t meet the high standards, putting them through a weeklong selection process to select only the best-qualified individuals. (U.S. Air Force photo/1st Lt. Katrina Cheesman)