Dr. Jack Shephard is a spinal surgeon and the de facto leader of the survivors of Oceanic Flight 815. Jack has control issues and trouble dealing with situations that he cannot fix. However, this attitude of solving problems through reason has given him the ability to function well during a crisis. Jack is, most of the time, in control of his life, emotions and situation he is in and is able to keep a cool head. Jack is commonly looked upon as the leader of the survivors who was mostly on good terms with everyone, especially Kate. However, ever since he cured Ben of his tumor, they were momentarily untrustworthy of his return with Juliet. Jack's rivalry of Locke escalated when he destroyed the submarine and ruined his chance to get off the island. Jack and five other survivors have managed to escape the island whilst using a helicopter from the freighter, although they left everyone else behind when Ben moved the island. Since rescue, Jack has learnt of his family relations with Claire and Aaron, has laid his his father to rest and was engaged to Kate. Unfortunately, ever since he has realised his sister is still on the island and Bentham has visited him, visions of his father have plagued him which has caused his resolve to collapse, leading him to be a broken man, becoming addicted to pills and an excessive alcoholic, whilst travelling on planes, hoping they crash, in a futile attempt to get back to the island.