Her Force wave had the desired effect. Well, it disoriented him long enough for her to put another approach together. Galen was right in thinking she wouldn't attack again unless he did. So as he got up and was looking for his weapon, Mara decided to insert herself to try and distract him more from this course of action.
"Galen, listen to me. I know you are upset, but you can't listen to the call of the Dark side. You can't let it control you, not now. It is not the answer."
She knew her words could backfire, or he would just ignore them and go for his weapon to attack again. Even with that in mind, she still tried because she needed to diffuse him. But he wasn't so far gone yet that she'd have to take drastic measures. Which is why she was trying to get him to listen to her again. But she was fully prepared to use the Force again should she need to.