Indeed, I am a Juvenile Ghost. When I'm wrong, I must reflect and correct my mistakes.
...
The door to the rooftop entrance was locked, with no keyhole, suggesting that it was secured from the inside with a chain or a U-lock.
Instead, the two started to smash the glass skylight. Although the glass was thick and hard, it wasn't bulletproof. It couldn't withstand their tampering and soon, a piece shattered and fell, crashing onto the heads of the zombies gathered below.
Lin Ma moved aside to wait in Stealth, and after 10 minutes, most of the zombies attracted by the noise had dispersed. Lin Wu, using a piece of rope they had cut, rappelled down to the 27th floor with Maya.