There is a massive earthquake that hits Gotham City. The people working for Wayne Enterprises feel the ground shaking, but while buildings are destroyed around them theirs stand well. Lucius Fox explains that all Wayne properties are built to withstand earthquakes of 8.5 on the Richter magnitude scale or worse. Thankfully his family is safe because he purchased his home from Wayne real estate.
There is tremendous disaster. The tallest skyscrapers crumble and fall into each other, leading to hundreds of deaths. Ruptured gas mains explode and there are massive fires. Gotham City Police Headquarters is hit and Commissioner Gordon is trapped in the wreckage. Barbara Gordon rolls into Police Headquarters and gets everyone's attention by firing a pistol into the air. She immediately takes control of the situation despite having no actual authority over them and starts organizing the police officers in the rescue efforts. It might seem like the end of the world, but all of them are in this together. Her motivational speech gets everybody working, saving lives and putting out fires. Harvey Bullock calmly walks in the front door with a metal pipe rammed halfway through his arm and quietly performs first-aid on himself by pulling it out with his teeth, then goes out to look for the Commissioner. Bullock rescues Gordon from underneath the fallen roof and reunites him with his daughter.
Wayne Manor has been completely destroyed... this was the only Wayne property that could not be quake-proofed because of the extensive cavern network underneath it. Batman pulls himself out of the ground, and rescues Alfred Pennyworth from the rubble. He determines that with the Batmobile broken, the only way to get into the city will be using his scuba gear through the underground streams, although he doesn't know how far they go. He gets into the extremely dangerous waters, and starts swimming down... then suddenly the aftershock hits.