Misery is the blast/AP move. We see that with how Big Mom uses her. She has misery slash down and punch, not shoot beams, because that's not what misery does. The blast is Maser Canon. Misery is a technique of Maser Saber
You're really twisting round to try and argue that Misery didn't attack Law when the panels clearly show that's what the homie was going to do.