Silent to the bone who really dropped Nikki?

In "Silent to the Bone" by E.L. Konigsburg, it is revealed that Nikki was accidentally dropped by her caregiver, Mrs. Coughlin, while trying to save her from falling. The incident leads to severe consequences, as Nikki falls into a coma. The story explores themes of communication, trust, and the complexities of relationships, ultimately highlighting the misunderstandings that arise from the incident.