We are having on relativly short talk for now.
It's not like Lash can whisper in our ear easily, she's living in Harry's head after all.
I'm not too worried that she will gain significant advantages from this talk and it will take some Charms to manage another one.
At which point we are an even harder target.
She seems to think she has something to gain, or she wouldn't bother talking to us.
They're really, really good at this. Almost everyone they interact with knows what they're like; that they're traitors led by a guy known as the father of lies, and they still regularly manipulate and suborn people.
Rule one of the fallen is that just knowing what they're like isn't any protection.
Just look at the last chapter. Lash starts off by lamp shading that she's a habitual liar and transitions directly into deceiving us with at best half truths while sounding reasonable to Molly.
I don't expect her to flip us in one conversation, but we have barely any defenses against what she's liable to try yet. Giving her an opening is just letting her lay groundwork while our guard is down.
I very much disagree that hearing her in this instance is hopping onto her mental operating table and asking her to surprise us.
She has been inside Harry's mind for three and half years at this point and Harry still hasn't picked the coin. I'm not saying that she is harmless but I doubt that she has some super complicated plan on how to use us for her own goals.
Harry is a ridiculous freak of nature befitting his status as protagonist, and she still got under his skin faster than almost anything else that tried recruiting him.
Harry has a lifetime of experience playing these games and his go to strategy is avoiding leaning on her as much as he can.
Molly, as an exalted, will likely exceed him in short order. But short order isn't the same thing as "before the dawn of the first day of her exaltation, with no useful prior experience to lean on".
The USS Hellfire is bullshit, but for the moment the captain is still a stressed out teenager who's in over her head. Lash doesn't need to improvise a complicated plan on the spot to exploit that.