Snape reeled back in outrage, and Harry pressed his advantage. In an instant his wand was in his hand, and he was blasting Snape backwards and into his office. Snape let out an alarmed shout, stumbling, knocked off balance, and landing heavily on the ground. Harry and Draco rushed in after him, and while Draco locked the door, Harry disarmed Snape swiftly and easily, snatching his wand out of the air and immediately passing it back to Draco (who fumbled with it for a moment, clearly as taken aback as Snape, before he slid it into his robe pocket).