Staff Sgt. Marcelo Mendoza and Spc. Richard Lee, members of the 569th Engineer Detachment (Dive), maintain positive control of the hoses that are supplying the divers below with breathable air during exercise Deep Blue in the Persian Gulf, July 26. Many of the scenarios test the divers on things that can go wrong from equipment errors to soldier injuries, explained 1st Sgt. Earnest L. Vance, master diver of the 569th.