She's pretty smart in that her motives regarding Rand have always matched her POV and her statements; in fact, the other Forsaken were probably taken in by how honest she was essentially being - namely, she didn't want to end up dead, she wanted to be Nae'blis...which meant not confronting Rand.

I'm of the opinion that as soon as the messenger showed up, she loaded him with Wards to determine where Rand was coming from/if he was channeling and then she escaped via Travelling as soon as possible.

She's not one to run from a fight but at this point A) she knows he has access to the Choedan Kal, B) holding the Power offers protection from Compulsion and C) her stated intention was to throw herself at his mercy or run away.

I think that once she knew Semirhage was captured and being punished, it would be clear that coming into contact with him without direct orders from the DO/SH is a big no/no. She's already been offered the position once, had a high position offered to her again in this book and quite frankly, I don't really see a motive for her to try mindtricks. At this point, she has quite a long list of Chosen that died to Rand - I don't think she'd try her chances fighting him directly. She may be a weak person, but I really do think she's pretty good at self-preservation - I expect she'll show up and be rewarded for causing Rand as much pain as she did without harming him. That's exactly why Semirhage failed and was being punished, and I think there are further uses for Graendal and Demandred - she was supposed to learn to obey the orders to the letter...cause Rand pain, and don't harm him. Semirhage couldn't even capture Rand without using her sadistic tricks and I think this is why she was forsaken. All she had to do was hold him in the a'dam and return to Moridin's fortress and she couldn't even accomplish that without engaging in some torture.