So the woman was going to try and reason with her. Once Leela was within a couple feet of Leia, she came to a stop and looked at her, the words of reason obviously falling on deaf ears. Leela had past the point of no return long ago when she'd attacked Anakin and Jaina. As far as she was concerned, killing Leia was the final step in avenging Romana.
"The time for talking is long past." True, Romana wouldn't want her to do this, but Leela wasn't thinking clearly, nor was she thinking for herself. She had always been extremely susceptible to mind control. The Doctor had been on the receiving end of that more than once before. But here, there was no Doctor who could recognize and reverse the mind control. Though this was more emotional control, but Leela was still very much Alema's puppet. And being the good little puppet girl, Leela was responding to the pull of her strings.
She lifted her right hand and drew her knife. "I will cripple you!" And with that, she launched herself towards Leia, ready to strike out with her knife.