Final answer:
Madam Lockton forbids Isabel from going to the prison in chains to maintain her power and prevent any potential disruptions or rebellious activities.
Step-by-step explanation:
Madam Lockton forbids Isabel from going to the prison in chains because she wants to maintain the appearance of authority and control over Isabel. By allowing Isabel to go to the prison in chains, it would undermine Madam Lockton's power and make her look weak. Additionally, Madam Lockton is likely afraid that Isabel's presence at the prison could lead to her involvement in rebellious activities or attempts to help the prisoners. By keeping Isabel away from the prison, Madam Lockton can prevent any potential interference or disruptions.