When Dror returned to the top floors he heard sounds of fighting coming from one of the halls and it was becoming louder as time went by.
The rebels had set up a barrier around the whole building but if the barrier got stuck by someone strong it would still be broken down and it seemed like whoever was fighting was trying their best to make as much commotion and sounds as possible to attract attention from outside.
But this won't last long as they will realize that there was a problem with the passage of time and no one comes to their aid, then they will notice the formation and attack it resulting in the commotion leaking out.
It would be best for the rebels if they were able to deal with the enemies before they noticed the barrier and Dror was also well aware of this, so he rushed towards the battle.