The Prince stopped it.
He could've been at Juliet's casket waiting for Romeo
Juliet is mad at the nurse in Act 3, Scene 5 of "Romeo and Juliet" because the nurse advises her to forget about Romeo and instead marry Paris. This conflicts with Juliet's feelings for Romeo and her desire to be with him. Juliet feels betrayed by the nurse's advice and feels alone in her struggle to be with Romeo.
Benvolio
Benvolio tries to stop the servants fighting.
Benvolio
When Romeo finds out that Juliet is 'Dead' he goes to see her in her tomb, and as Paris is there, he tries to stop him from seeing her, thus Romeo kills him.
It is unclear why Paris is at the tomb, but he is killed by Romeo in a duel. Paris dies defending Juliet's honor and seeking to stop Romeo from disturbing the tomb.
The song we are family
Because she doesn't stop Romeo
When Romeo finds out that Juliet is 'Dead' he goes to see her in her tomb, and as Paris is there, he tries to stop him from seeing her, thus Romeo kills him.
Juliet says she would deny her family and change her name in order to be with Romeo.
Friar Laurence tries to stop the fight between Tybalt and Mercutio but is forced to intervene when Mercutio is killed. This event sets in motion a chain of tragic events that ultimately results in the deaths of Romeo and Juliet.