Merlin doesn't have to be told twice. Even in the midst of this absolute chaos, what needs to be done is obvious and there's only one way to clear the path. He glances back briefly at the others and gives a small but resolute nod. He's never been good with words and there isn't time for them now anyway, but he's got their backs. He's ready to go through hell with them. Then he turns, taking off quickly after Mr. Purcell with his Draco Nine Tails in his hand and wand secured in his jacket's inner pocket. He silently readies himself for the first monstrosity that gets in the way.