How do Kate and Constance visit the boys' room each night?

Kate and Constance visit the boys' room each night by crawling through ceiling panels. This method highlights their resourcefulness and ingenuity, as they take advantage of the school’s architecture to move between rooms without being detected. The ceiling panels serve as a clever means of maintaining secrecy and enhancing the narrative’s adventurous tone. Their ability to navigate these hidden routes also reinforces themes of collaboration and friendship, illustrating how they work together to overcome challenges and connect with their companions.

The other methods are not employed in the story. A secret door in the hallway, a hidden passage behind the wardrobe, or climbing down the fire escape would suggest different dynamics that don’t align with the established methods of movement utilized by the characters in the context of the book.