these four guys with their helmets are about to receive miss polyxena in order to sacrifice her to appease the wrath of Achilles. They propably are Neoptolemus, the son of Achilles, and his comrades in arms Odysseus, Ajax and Diomedes. This is part of a religious ceremony among Hellens, including the two musician ladies in front of them. The lyra player ,her left hand pointing downwards, seems to speaking to the men and telling them that this sacrifice has to be done, that her blood must flow. What I don't understand is why these soldiers are on their toes. Perhaps it is a gesture frozen in time