Half an hour passed. The people outside had already begun breaking down the door using other methods.
But at this moment, inside the room, cracks finally began to appear on the metal walls under the continuous effect of the High-Frequency Vibration. Then, under Lin Yue's still-shocked gaze, the cracks gradually spread, covering the area within the marked circle like a spiderweb.
Cheng Zongyang immediately increased his Energy output.
The next moment, with a loud CRACK, the metal wall shattered. Pieces crashed to the floor with dull thuds, revealing the mountain's bare concrete wall underneath!
