A rectangular box embedded into the wall, fitted with a numeric keypad.
Xia Lihua stepped closer, examining it carefully. "We need to use the passcode to go across this door..."
Yang Lingyun leaned slightly toward it, eyes narrowing. "It's a timed lock system."
Xia Lihua glanced at him. "Meaning?"
"Limited attempts," he replied. "Get it wrong too many times, it triggers an alert—or worse, locks permanently."
She exhaled lightly. "Great."
A brief silence followed as both of them studied the panel.
"I'm not good at hacking," Xia Lihua admitted, crouching slightly to inspect the edges. "But mechanical locks—I can manage."
"This isn't mechanical," Yang Lingyun said. "Using your compact tools won't work on it. If you tamper it or use force, it might trigger the alarm system. We can't risk it."
"Then what do we do?"
"Permutation and combination," Yang Lingyun explained. "The code isn't random. It's structured—likely based on a pattern, sequence, or logic tied to the facility."
