Behind him, Draco said nothing, but Harry could practically feel his nervous energy pouring off of him in waves. Harry narrowed his eyes at the professor, swiftly assessing the likelihood of them persuading him to cooperate and finding it to be somewhere near zero. Fortunately for them, Harry had lots of experience in dealing with people who were unwilling to speak to him - he might not have been an Auror for years now, but he was sure he would manage. He glanced furtively up and down the corridor, and finding no one there, he tried a firmer approach, "Sorry Professor," he said, "but we’re not taking "no’ for an answer today," Harry had no illusions that he could physically overpower the potion’s professor, but magically? Well, he’d always been very successful when it came to pursuit and capture, and Snape was hardly expecting to be attacked by a fifteen-year-old boy.