What is the importance of the "ledge" in the novel, All the Bright Places?

Although it is also a setting, the ledge of the school’s bell tower becomes a symbol for Finch and Violet of their grief and thoughts of suicide. At one point in the novel Finch encourages Violet to get off of the ledge of grief she’s created for herself. In another section, Violet tells her parents Finch is on the ledge, meaning he’s in trouble and needs their help.