He spread his hands out on the desk and nodded once. "You're free to go now," he said. "I'll see you again on Tuesday for another detention." He would have to bear the consequences of whatever he told her, though he guessed, seeing that she didn't believe a word out of his mouth, that it wouldn't be so bad.
"Tell Miss Weasley not to lose the map again," he said. "None of the other professors will be quite as nice about it, and Prongs will have my head if it gets destroyed." A beat. "Have a good night, Miss Bones."