While Antinous is drinking his wine Odysseus shoots him in the throat. They then started yelling in outrage at Odysseus for what he had done. There was no defense, so every suitor died, soaking in the smoking blood. This scene is vital because without killing all of the suitors, Odysseus couldn't have made sure that he got his wife back. The suitors probably would have made a big deal out of how Odysseus just got his wife back after 20 years of being missing in action, and they had gone through all of that work to marry her.
"Foul! to shoot a man! That was your last shot!" "Your own throat will be slit for this! "Our finest lad is down! You killed the best in Ithaca." "Buzzards will tear your eyes out!"