You place one of your feet on the slave in front of you, as to keep him down, and repeat the signals "fight" and "sleep", "Fight" and "Sleep" over and over again. The leg-scarred slave perks up, nods his head, and mutters something to the other two slaves. They nod, and look you in the eye.

You bash the downed Slave on the head with the butt of your spear, knocking him unconscious, and beckon for the slaves to come at you, bro.

You feign the entire fight, and put on a great show for the crowd. You look up at the noble, and see a FIST CLENCHED WITH THE THUMB INSIDE (historically correct, signaling for kill, sorry for the wrong gesture earlier) signaling for you to kill them all.

1. Execute them
2. Don't kill them