When Danielle "Dani" Clayton (Victoria Pedretti) first arrived at the home in The Haunting Of Bly Manor, she was greeted by the ghost of Hannah Grose (T'Nia Miller), whose life she could've saved had she arrived minutes sooner — here's how.
The Haunting Of Bly Manor is Mike Flanagan's highly anticipated follow-up series to The Haunting Of Hill House. Its story is adapted from several Henry James ghost stories, but the foundation comes from his 1898 novella, The Turn Of The Screw, which has been considered one of the most influential horror stories ever written. The first installment in The Haunting series notably adapted Shirley Jackson's The Haunting Of Hill House, and starred several of the cast members who returned for Bly Manor. Victoria Pedretti portrays Dani, a young woman who has recently been hired by Henry Wingrave (Henry Thomas) to care for his niece, Flora, and nephew, Miles. The children lost their parents in a tragic accident two years prior to Dani's arrival in 1987. Hannah Grose is Bly's housekeeper, who has cared for them for years, and can often be seen lighting candles in the church on the manor's property in remembrance of the dead.
Dani first meets Hannah after walking through the woods on the massive property; she finds her standing over a well. It is not revealed what she is looking at until Miles - who was possessed by the late Peter Quint (Oliver Jackson-Cohen) at the time - takes her to the well in The Haunting of Bly Manor episode 7, "The Two Faces, Part Two." As she leans over, Hannah Grose discovers that she is dead. She was pushed into the empty hole by Miles, and has been dead since minutes before Dani's arrival. So how could the governess have saved Hannah's life?
After accepting the job as Flora and Miles's au pair, Dani is driven to Bly by Owen (Rahul Kohli), who works as a chef at the manor. Once she sees the side of the building in the distance, she asks Owen to stop the car so she can walk the rest of the way. She notices Flora singing by the lake, and stops to have a conversation with her until the two walk to the well to meet up with Miles and Hannah together. What she doesn't realize is, the time she spent walking and talking with Flora was also the exact moment that Hannah died from being pushed into the well. It's not brought to anyone's attention because Dani arrives in the midst of Hannah's self-mourning, and there is barely an inkling of anything being amiss.
If Dani hadn't gotten out of the car and allowed Owen to drive her to the front door instead, it's entirely possible that Hannah could've seen them pulling up to the manor and walked away from her dreadful fate. Dani's ability to save Hannah's life is relies on what time she would have arrived at Bly Manor if not for her decision to walk the rest of the way. The walk she took forfeited her ability to stop the nanny from falling down the well. Even if she hadn't stopped to speak to Flora, she could've potentially stopped Miles from pushing her in.
While Dani could've saved Hannah's life by staying in the car instead of driving, there is no telling how this would've impacted Peter Quint's possession of Miles, and the climactic moment where he forces Hannah's spirit to look at her dead body in the well. Perhaps Hannah could've gone on to live happily with Owen in Paris, but it's far more likely that, had she not died before Dani's arrival, she would've died at another point in the series. It was always fated that Hannah Grose would die in The Haunting Of Bly Manor, regardless of whether or not Dani drove or walked.