I'm not sure they felt his drawing on the CK without channelling, but for the sake of the argument, let's say they did.

... by the time Rand goes on Dragonmount, news must have spread among the remaining Chosen that Rand has gone ballistic. Not only Semirhage has suddenly died, and so did Elza who was probably Mesaana's/Demandred's spy (what really went on is probably a puzzle to all but maybe Moridin, and a big secret.. if the Chosen learn Rand was granted access to the TP to kill one of them... loyalty to Shai'tan is going to take a massive and sudden dive and short of mindtrapping the three remaining Chosen, Shai'tan can probably count them out) but more relevant, the Chosen must have learned by now Graendal died, and how she died. Rand has long got access to san'angreal without carrying them around and using them systematically in all his fights (the fool, Demandred must think), but if he's so far gone that he now uses the CK as a weapon and isn't afraid to balefire whole palaces with it (which would rejoice only Shai'tan and Moridin, for whom Rand unravelling the Pattern is the same as Shai'tan breaking the Wheel). Coupled that with possible reports from DF in his entourage in Tear that the "inner circle" is in an uproar and Rand has fled after a big confrontation with Cadsuane and Nynaeve... I'd say when Demandred and Aran'gar felt Rand draw on the CK near or at TV, they made sure they'd be nowhere where they have their habits, just to be on the safe side in case Rand was proceeding to eliminate all the Chosen with balefire and seemingly had located the well-hidden Mesaana after the well-hidden Graendal ("he has figured out about transmigration", they might conclude, and for the locations they might worry they've been betrayed). They probably both sought their spies to learn what was going on... The first thing they probably wondered about is if Rand had just balefired the WT, and if this was to kill Mesaana or as a result of his confrontation with AS near him.

Mesaana, like Egwene etc. must have no idea what danger they've been in that day.

Even Demandred must be getting a bit less eager about a confrontation with Rand these days. Demandred is cold and logical, a strategist apt at calculating the odds and good at playing them. He's prepared to face Rand/LTT. The man who killed Graendal wasn't the same foe Demandred planned for. From afar he now has all the appearance of being a madman, totally unpredictable, who won't necessarily make logical moves and who does things LTT would never have done (like not caring about collateral damages or the precarious state of the Pattern anymore) making him much more dangerous, and very hard to puzzle out. From Demandred's perspective post-Graendal, facing Rand is now pretty much like going after a Moridin who carried the CK and wants him dead.

It's if/when the Chosen learn the CK has been destroyed that Rand will be in extreme danger. If Rand is even a bit clever (and he usually is...), he will keep that fact to himself, letting everyone believe he still has the CK. Unless Moridin/the DO think the time has now come to kill Rand because of his epiphany, he's probably gonna keep what he knows of the destruction of the CK a big secret, otherwise Aran'gar, Demandred and Mesaana (and maybe even Cyndane, the only one who is crazy enough to try to kill Rand despite knowing Moridin will kill her for that, or Shai'tan will) will see in that their chance to kill Rand, before he gets Callandor back, and whatever Moridin orders Demandred and Aran'gar might be too disturbed by Graendal's and Semirhage's deaths not to attempt something soon... if they learn he no longer has the CK, anyway.