Compulsion wouldn't allow Ramshalan to retroactively mind-read Rand, you know.

I suggest you reread that passage, what Rand says is that Graendal is so much smarter than him and that he has no way of matching her, and that he needs to get some allies who are more clever than her (to say nothing of that absurd idea about allying with Graendal, which she surely wouldn't buy after Sammael tried that trick), there is nothing that indicates that Rand is going to balefire her palace in the next few minutes (or days, or even weeks), everything in that conversation suggests Rand is stumped and is unable to find an answer to dealing with Graendal.