What does Harry do to escape from Lea?

Michael and Thomas distract Lea long enough for Harry to eat a poisonous mushroom. Harry tells Lea that even with the antidote Michael is carrying, he will need hospital treatment to survive, and since he is no good to her if he is dead, it is in her best interests to let him go. She agrees, but points out that his friends do not have safe passage; Harry runs, while Michael and Thomas stay behind to fight Lea and her hell-hounds.