Broadcasted on December 8, KBS 2TV's 'Entertainment Weekly' featured the 'school attack' segment where Red Velvet made a surprise visit to the Korea Military Academy.

Upon seeing the popular idol group the faces of the military students lit up as they gave the girls a warm welcome into the lecture hall.

via GIPHY

The military students dressed in uniform had no clue what was happening, as they seemed bewildered and surprised by the sudden appearance.

Red Velvet also presented a live performance of "Peek-A-Boo" in front of the class, and took the time to interact with the military students.