To shoot something in a dream, means that you already made a target and aimed to reached it as soon as it is possible. In those cases when the dreamer shoots the other human being, such dream shows the aggressive emotions towards certain person or situation. If someone has shot you with the gun, then it could reflect the relationships between you and somebody else. Maybe you are in a conflict with somebody and afraid of the consequences.
Dream dictionary: aimé dream meanings
(Destroy | Extirpate | An assault which is directed by an enemy or which is aimed at an enemy.) An assault in a dream means a disaster, a calamity, a flood, a fire, locusts or major changes in the world. To devastate someone by looking at him with despise in a dream means that the assailant will suffer from the jealous eye of his victim in wakefulness.