 Admiral Bates states that Ryback lead a SEAL team to take the  airport in Panama and was the only survivor of the team. In one of  the major blunders of the Panama invasion SEAL team 4 was sent to  take the airport. In that mission 4 SEALs were killed and 8 were  wounded. Generally, Army Rangers take airports but the Navy was  unhappy with the amount of participation in the invasion so the  SEALs were given the task.