Maybe he'll learn fom experience and keep his knife on him. Remember he'd left in his room when he could have used it in the second task. He should have had it on him for the third task (but I think his hands were too well bound to use it).

"The world is indeed full of peril, and in it there are many dark places; but still there is much that is fair, and though in all lands love is now mingled with grief, it grows perhaps the greater."
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