The student's paper is thin enough that you get the sense of his pattern. It's a force pattern, likely to hold your car's door shut.
Your patterns are always at hand. You rifle through them and select one of redirection. You'll turn his magic back on him.
You stare at the pattern, letting it seep into your mind. Then you wait.
As the student looks up from his paper, you channel energy through the pattern in your mind. It envelops the magical energy from the student and sends it back at him. The force rebounds. Tiny round leaves flutter as the force returns to the student and pins him against the red brick wall.
You step out of your car. "Next time, be faster. Even better, be unseen."