Since Capt Rajveer and Abhimanyu are currently in a situation where they misunderstand each other, they challenge each other... and they will use the cadets as pawns... so Capt Rajveer will incite the cadets to rebel, whereas Abhimanyu will try to supress the rebellion.... here they are fighting each other through the cadets.... by calling Naina, what Abhimanyu did was that he made it possible for Capt Rajveer to talk to the cadets.... so that the challenge could begin.