what goes wrong with the childrens escape plan? At whom does Mr.nathan think he has fired his gun?

Jem and Dill hatch a plan to leave a note for Boo in the Radley's window, using a fishing line. The note will ask him to come out sometimes and tell them what he's doing inside, and that they won't hurt him and will buy him ice cream. Dill says he wants Boo to come out and sit with them for a while, as it might make the man feel better. Dill and Scout keep watch in case anyone comes along, and Jem tries to deliver the note with the fishing pole, but finds that it's harder to maneuver than he expected. As he struggles, Atticus arrives and catches them all. He tells them to stop tormenting Boo, and lectures them about how Boo has a right to his privacy, and that they shouldn't go near the house unless they're invited. He accuses them of putting Boo's life history on display for the edification of the neighborhood. Jem says that he didn't say they were doing that, and thus inadvertently admits that they were doing just that. Atticus caught him with "the oldest lawyer's trick on record."

A white negro