Wild Child - S2-E6
Corrected entry: When TJ says, "Hang on kid, I think this fountain might be a trap.", there's a security 6th grader in front of the fountain, leaning up against it. But when Randall runs by and says "Hey, let me play or I'll make up something to tell Mrs. Finster on you.", the 6th grader has moved way to the left of the fountain.
Correction: He was never leaning against the fountain. It just looked like he was from where TJ was.