Othello is in a blind rage confronting Desdemona about her cheating with Cassio. No sense can be talked into Othello , as he is about to kill Desdemona.
But while I say one prayer!
It is too late. (he smothers her)
Desdemona is pleading with Othello Hoping that he will not kill her, trying to buy some time and prove her innocence. To prove that she is not cheating. But Othello is having none of it.
This is the final moment where there is no going back. Othello is considering if he should kill the love of his life.
(offstage) My lord, my lord! Hello! My lord, my lord!
This is what the whole book has been leading up to. All of Othello's plans and schemes have come to this very moment. Othello killing his wife. Othello has done this under false information but the main goal of Iago has been fulfilled.
Emilia will soon enter the stage and be the one to witness Othello's murder of her master. This is insurance for Iago to make sure that someone sees that Othello killed Desdemona. Iago is the winner for now.
What’s that noise? Aren’t you dead yet? I know I’m cruel, but I’m merciful too. I don’t want you to linger in pain.