Why do i keep killing in my dreams?

I have those- i'm not a violent person at all. But see, the focus of the dream isn't the killing, the focus of the dream is protecting your mom. not only that, but a dream takes less than a second to happen, but your mind expands it into what seems like a longer event, so one single thought could be expanded into a dream, so the thought of protecting your mother could be expanded into a dream, and your brain fills in the blanks as it goes, creating a threat for you to protect her from, etc.