If I stab you through the eye, I doubt you'd call it something existing in my mind as the spike would be in yours.

Stabbing is the physical act, good or bad is a value judgement that exists in your mind.

If someone is committing rape upon your mother and you stab them in the eye, the act would be good from your perspective.

The same act of stabbing can be bad if committed under different circumstances.

We can choose goodness or evil in every decision, impacting each other along the way for good or bad.

Good and evil are concepts that only exist in the human mind. Things just are, there is no good or evil in the grand scheme of the universe.