"Mr. Potter!" Harry’s mouth snapped shut. Dumbledore had never raised his voice at him before, and he couldn’t say he liked it. "I understand that you must feel responsible, given the knowledge you hold, and I commend you for wanting to improve upon events of your past. However, time is a tempestuous mistress, and meddling never turns out for the best. Whatever you would like to tell me you must keep to yourself, and trust that I will do what is needed of my own volition."