We see Othello's mental stability deteriorating in this scene. Earlier with Iago, he "falls into a trance." After overhearing what he thinks is Cassio discussing an affair with Desdemona, he becomes angry. He strikes Desdemona in front of Lodovico, who has just arrived in Venice, without directly accusing her or explaining his anger. Lodovico is of course shocked by this action of the noble man: Othello is throwing out social etiquette, a change from his behavior earlier in the play.
His final speech in this section reflects his troubled mind:
Ay; you did wish that I would make her turn:
Sir, she can turn, and turn, and yet go on,
And turn again; and she can weep, sir, weep;
And she's obedient, as you say, obedient,
Very obedient. —Proceed you in your tears.—
Concerning this, sir,—O well-painted passion!—
I am commanded home. —Get you away;
I'll send for you anon. —Sir, I obey the mandate,
And will return to Venice.—Hence, avaunt!
Cassio shall have my place. And, sir,...
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