De como eu vi (no filme, nenhum indício sobre a novelização):
She didn’t succeed at tapping into the Force for the mind trick attempt. And his reaction was just "Uhm what did that lousy prisoner just say? Are you kidding me? You are going to pay!” So he was just angry at being talked to in such a commanding tone with idiotic commands by a mere prisoner and reacted accordingly. That is, until she managed to tap into the Force at long last.