See I don't agree with the it's not Odium because he's scared reasoning. He might not want a direct confrontation, as that would be kind of foolish. But what we're seeing isn't a direct confrontation. It's a death of a thousand cuts from pawns and feints. Odium to accomplish his plans needs to confront Sazed regardless of his fear.
On a goofy note, don't forget the words of Master Yoda, "Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering."
Odium is hatred.