Juliet's inability to run away in Act 4 stems from societal and familial pressures, lack of freedom for women in the Elizabethan era, and the tragic outcome of her and Romeo's rebellion against these constraints.
In Shakespeare's Romeo and Juliet, the concept of Juliet running away in Act 4 is complex due to the societal and familial constraints of the time. Juliet's situation is dire because she faces immense pressure from her family to marry Paris and her secret marriage to Romeo creates conflicting loyalties.
Moreover, as a woman in the Elizabethan era, her ability to move freely and make autonomous decisions is severely restricted, making escape a difficult and potentially dangerous endeavor. The climax of the play illustrates the tragedy and consequences of the lovers' defiance against these societal norms.
Throughout the play, we are shown how the lack of communication, the haste of decisions, and the cultural restrictions lead to the heartbreaking and inevitable end of the star-crossed lovers.