From Chauvelin she knew that she could expect no mercy.

He had set a price on Armand's head, and left it to her to pay or not, as she chose.
Later on in the evening she caught sight of Sir Andrew Ffoulkes and Lord Antony Dewhurst, who seemingly had just arrived.

She noticed at once that Sir Andrew immediately made for little Suzanne de Tournay, and that the two young people soon managed to isolate themselves in one of the deep embrasures of the mullioned windows, there to carry on a long conversation, which seemed very earnest and very pleasant on both sides.
Both the young men looked a little haggard and anxious, but otherwise they were irreproachably dressed, and there was not the slightest sign, about their courtly demeanour, of the terrible catastrophe, which they must have felt hovering round them and round their chief.
That the League of the Scarlet Pimpernel had no intention of abandoning its cause, she had gathered through little Suzanne herself, who spoke openly of the assurance she and her mother had had that the Comte de Tournay would be rescued from France by the league, within the next few days.

Vaguely she began to wonder, as she looked at the brilliant and fashionable in the gaily-lighted ball-room, which of these worldly men round her was the mysterious "Scarlet Pimpernel," who held the threads of such daring plots, and the fate of valuable lives in his hands.
A burning curiosity seized her to know him: although for months she had heard of him and had accepted his anonymity, as everyone else in society had done; but now she longed to know--quite impersonally, quite apart from Armand, and oh! quite apart from Chauvelin--only for her own sake, for the sake of the enthusiastic admiration she had always bestowed on his bravery and cunning.
He was at the ball, of course, somewhere, since Sir Andrew Ffoulkes and Lord Antony Dewhurst were here, evidently expecting to meet their chief--and perhaps to get a fresh MOT D'ORDRE from him.
Marguerite looked round at everyone, at the aristocratic high-typed Norman faces, the squarely-built, fair-haired Saxon, the more gentle, humorous caste of the Celt, wondering which of these betrayed the power, the energy, the cunning which had imposed its will and its leadership upon a number of high-born English gentlemen, among whom rumour asserted was His Royal Highness himself.
Sir Andrew Ffoulkes?
Surely not, with his gentle blue eyes, which were looking so tenderly and longingly after little Suzanne, who was being led away from the pleasant TETE-A-TETE by her stern mother.

Marguerite watched him across the room, as he finally turned away with a sigh, and seemed to stand, aimless and lonely, now that Suzanne's dainty little figure had disappeared in the crowd.
She watched him as he strolled towards the doorway, which led to a small boudoir beyond, then paused and leaned against the framework of it, looking still anxiously all round him.
Marguerite contrived for the moment to evade her present attentive cavalier, and she skirted the fashionable crowd, drawing nearer to the doorway, against which Sir Andrew was leaning.