Answer:
He uses the sword fight to depict conflict.
Explanation: If you are referring to the sword fight that they had, they used the stage direction to show that Mercutio was disgusted of tybalt, and was mad, and stabbed him through Romeo's arm. So a flat out answer, Shakespear uses the stage directions of Mercutios emotions and movements to show conflict between mercutio and tybalt, leading to tybalt stabbing mercutio.