Mikey smiled ruefully. "Sometimes he smokes up on top of the gargoyles," he offered, hoping Gerard wouldn't kill him for passing over that piece of information. "Anytime soon the bats are going to start talking to him. Or someone's going to wonder what that weird smell on the roof is and find him."
That only helped if you got him at the right time, though. "Or you could try grabbing him when he's doing work stuff. Get some first years to start a fire during his patrol hours and then stand next to it."