One of these moments is when she talks to Mark Fossie and decides to go back to "normal" to make him happy. Her moral nature motivates this action and tells of her that she truly cares about Mark. In the end, his unstable personality prevails over this moment of emotional weakness and he returns to what he was becoming. Mary Ann undergoes a drastic moral and emotional change through a gradual process. The girl who arrives in Vietnam would not have been able to hunt and kill without a second thought, much less enjoy it. Maybe it's always been in his character, it's just never been questioned, but eventually this all happens. Mary Ann is a well-rounded character and has a complex temperament. At first she is a sweet and loving girl that every soldier becomes fond of. Then she ends up going crazy from the killings and obsessed with Vietnam. Yet, in this transition, she is still in love with Mark Fossie, but unlike when she got there, her motivation is no longer so.