But that they shall not die, while I have the power to preserve them, is my resolve and my duty! Life, then, for life; yours for this family!" Wallace, directing his voice toward the keep: "The moment," cried he, "in which that vile cord presses too closely on the neck of the Earl of Mar, or any of his blood, the ax shall sever the head of Lord de Valence from his body!" De Valence was now seen on the top of one of the besieging towers.

He was pale as death.

He trembled, but not with dismay only; ten thousand varying emotions tore his breast.

To be thus set up as a monument of his own defeat, to be threatened with execution by an enemy he had contemned, to be exposed to such indignities by the unthinking ferocity of his colleague, filled him with such contending passions of revenge against friends and foes, that he forgot the present fear of death in turbulent wishes to deprive of life all by whom he suffered.
Cressingham became alarmed on seeing the retaliating menace of Wallace brought so directly before his view; and, dreading the vengeance of De Valence's powerful family, he ordered a herald to say that if Wallace would draw off his troops to the outer ballium, and the English chief along with them, the Lord Mar and his family should be taken from their perilous situation, and he would consider on terms of surrender.
Aware that Cressingham only wanted to gain time until De Warenne should arrive, Wallace determined to foil him with his own weapons, and make the gaining of the castle the consequence of vanquishing the earl.

He told the now perplexed governor that he should consider Lord de Valence as the hostage of safety for Lord Mar and his family, and therefore he consented to withdraw his men from the inner ballium till the setting of the sun, at which hour he should expect a herald with the surrender of the fortress.
Thinking that he had caught the Scottish chief in a snare, and that the lord warden's army would be upon him long before the expiration of the armistice, Cressingham congratulated himself upon this maneuver; and resolving that the moment Earl de Warenne should appear, Lord Mar should be secretly destroyed in the dungeons, he ordered them to their security again.
Wallace fully comprehended what were his enemy's views, and what ought to be his own measures, as soon as he saw the unhappy group disappear from the battlements of the keep.