Final Answer:
Mistress Lockton hit Isabel at the docks because Isabel intervened to prevent Mistress Lockton's husband from being trampled by a horse.
Step-by-step explanation:
The event where Mistress Lockton struck Isabel at the docks is a critical plot point in the narrative. In the story, Isabel, a slave, witnesses Mistress Lockton's husband being in danger of being trampled by a horse at the docks. Acting on her instinct and empathy, Isabel rushes to intervene, attempting to save Mr. Lockton from harm. However, Mistress Lockton reacts violently, striking Isabel as she perceives Isabel's actions as insubordination and interference in a matter involving her husband.
This incident serves to highlight the power dynamics and brutality within the historical context of slavery. Isabel's act of compassion is met with physical punishment, showcasing the dehumanizing treatment faced by enslaved individuals. Mistress Lockton's violent response also reflects the sense of entitlement and cruelty that slaveholders could exhibit, emphasizing the harsh realities of the time. The event not only shapes Isabel's character but also contributes to the broader exploration of themes such as oppression, resistance, and the dehumanizing impact of slavery.
Furthermore, this pivotal moment propels the narrative forward, influencing Isabel's journey and relationships within the story. It deepens the emotional and thematic layers of the narrative, shedding light on the complexities and hardships faced by enslaved individuals as they navigated a world marked by cruelty and injustice.