Continuity mistake: When Briseis is about to kill Achilles he turns her over and his hand slids down to the edge of her dress and then up her leg to her shoulder. However in the next shot his hand is only at her waist and slids up to her shoulder again.
Continuity mistake: The position of the three ropes that hang on the horse's head vary, between when it is first seen on the beach, when it is pulled into the city, and when it is finally placed outside Poseidon's temple. Because they are wrapped around its head, there's no way that they'd be able to move.
Continuity mistake: When Achilles is burning Patroclus' body, the moonlight reflects slightly off his arms. While a body is burned, a person with a torch is always beside the one who places the coins, so the firelight would've shined off Achilles' arms as well, and yet it doesn't, indicating that the scene was not shot continuously.
Continuity mistake: After the Trojans were ordered to push forward after the Greek's first attack, blood can be seen suddenly appearing on a few of the Greeks shields.
Answer: He was warning the other soldiers that Achilles was coming.