Mara could tell that her words had at the very least given him pause, allowed a struggle within him to try and break the the captivating call the Dark side had. But she knew that also wasn't enough. Her danger sense had been telling her to be wary ever since she'd felt that spike in the Force that caused her to come searching for Galen.
When she saw the tear escape his eye, Mara could clearly see the storm of emotions he was having. She didn't have to have the Force to see through the cracks in the walls he held around himself. All right, that was something at least, but Mara was still wary. Her danger sense went on complete high alert as Galen said he'd make her move and then when his lightsaber was activated.
In that moment, Mara decided she should act. As much as Galen may need the release of a fight, Mara knew someone tempted by the Dark side was more willing to do anything to get what they wanted. And that was not a battle she wanted to happen. She'd rather take care of this without the rest of the Force users here sensing it and coming to get involved. So as Galen studied her, Mara acted.
Calling upon the Force, she used a Force whirlwind to grab Galen and pull him up into the air, spinning him around and holding him upside down within its grasp. She had initially thought to use a Force wave, but she wanted to get out of this with as little destruction as possible. So she'd opted for the whirlwind instead. At least this way, Galen couldn't attack her directly, and she would knock him out if she had to. But for now, she was settling for spinning him around and incapacitating him in a physical sense.