Creak of the Door
The sound of the door creaking causes Heracles sons to jump up expecting him to be there. It is a symbol to them that he is home to protect them from the fear that presses upon their hearts as Lykos is setting out to kill them.
Age
Amphitryon speaks of how he would kill Kykos if he were a younger man. His old age is a symbol for how time steals the strength from even the bravest of men, and keeps them from performing any task.
Old Men
The Chorus is made up of the Old Men of the city. They all defy Lykos, but are incapable of stopping him. They are a symbol of having a strong will but the inability to fight the injustice.
Burned Alive
Being burned alive is a symbol of cowardice by Megora. Thus, she will not allow Lykos to inflict this fate upon her. She plans to dress her sons and prepare them for execution.
Exile
Megora would rather have her sons be executed then sent away in exile. Indeed, exile is a symbol of poverty, which is a worse fate than death.