You grabbed him, then and there.

Deciding there was no point in being subtle, after all, the entire palace knew you were there; you burst out of your hiding place. You dispatched the guard with a clean stab to the throat before he even turned to look at you. Then a quick kick to the Duke’s neck, snapping it, and the room’s number of living occupants had been cut neatly in half.
Barely ten seconds had passed and the poor young beauty was staring in open-mouthed shock at you. You grinned at him and swept forward. He had the presence of mind to attempt to jerk away, but you had hold of him before he could get more than a foot. You put a hand over his mouth and took a moment to take him in up close and personal.
The eyes were an even deeper shade of blue than you’d thought, glaring at you as he struggled. His skin was almost ghostly pale, but suited him in a perfect contrast to his ebony hair. His body in your arms was slender but strong, with hidden muscles flexing under his clothes.
“Don’t worry precious; I’m not going to hurt you.” His eyes narrowed and you almost laughed. His defiance was cute.
However, time was moving along and you needed to make a move. You applied enough pressure at the base of his neck to make him pass out, and then slung him over your shoulder. You poked the Duke with your toe, but he was definitely dead. Yet another job done well, albeit messily.
With your prize firmly in hand, you made your way out.