Confused was not something Galen was familiar with in a fight. He had a good battle and survival sense. But for whatever reason, he he had no kriffing idea whatever that had been of what Mara had just done. He was definitely off-guard. But he collected himself quickly, thinking fast of what he could try to do to catch Mara off-guard. A move came to mind and he wrestled with the idea of using it. Mara was a Jedi. And if Jacen was right, and Galen had no reason to doubt his friend, then Mara would start trying to dissuade him from using his Dark powers.
But Galen wouldn't be shaken in the beliefs he shared with Jacen. The Force was a weapon. All sides should be implemented in a fight for the greater good. The means justified the power. Besides, he would control the voltage and make sure she didn't get hurt. If she even got hit. It would just feel like one of those taser thingies a thug had used on him once.
He shut his saber down and slid it into his pocket for a moment. He held his arms down at his side, slightly away from his body. Closing his eyes, he focused and opened his palms, electricity sparking around his fingers and forearms. Galen next raised his arms and sent the arc of lightening at Mara, making sure it wouldn't do any damage to her.