An accident? Can it truly be an accident! The one who knew the answer was questioning the other who was clueless and what was his intention by doing that?
Theo gut feeling was telling her that the thing that happened to her father was not just an accident but a pre-planned murder and how can she not feel that when from the moment she came here, many people were after her and her father's life.
So, was he playing with her some words game that made him ask her what if everything was accidental!
"Assume what you want, that's none of my business but I am not going to sit around". Theo boldly made herself clear, her eyes that had no hope earlier was shining as if it was burning to get revenge.
Nanny Ai panicked since if Theo really wanted to get revenge then she might get injured, too, or maybe end up being killed and she doesn't wished for that to happen.