Why didn't the whitey cross the road?

The sirens started early in my walk to the Post Office. At first, I thought there must have been a terrible accident and this was the sound of a fleet of ambulances rushing to the scene. As I walked further, each step closer to the sound, I saw no ambulances and no signs of life at all. I reached the Post Office on the corner of a busy intersection. The sirens were now booming. The cars were lined up, packed in perfect symmetry as if they'd been planning this drill for days. There were officers in the middle of the intersections making sure no car dare take to the road. I went in the Post Office and took care of my business. Upon leaving, I noticed that Korea was still paused. I began to cross the street when an officer blew his whistle and yelled something I'll never understand. I backed up on the sidewalk and stood there baking under an intense sun, dumbfounded and embarrassed. I'm sure every person parked in their cars was having a laughing fit looking at the confused foreigner. Still, I couldn't hear their laughter because I was the only person on the street. In the height of my bewilderment, one of the cell phone salespeople from the Post Office beckoned me to come inside. We spoke in Korean and I asked her why I couldn't cross the street. I couldn't understand her reply to this, but she told me I wouldn't be able to leave until 3:00. It was now 2:15 and I had to teach at 3. She offered me coffee and told me to sit and wait it out, whatever it was. I asked to use a phone to call my school and just then, like someone had pressed the play button, life resumed at its usual frantic pace. Back at work, I asked my co-workers why I was trapped at the Post Office. This, they told me, was a drill in preparation of a North Korean attack. The people all go inside and, if possible, into bomb shelters. The drill stresses more than simply physical preparations. Everyone is practicing a sort of meditation, maintaining calm amidst the chaos. Certainly, it is important to act with poise, if possible. South Korea used to do these drills monthly but, due to the recent peace, the drills only occur 3 times a year now. That being said, I'm fortunate I was caught in the middle of one, but I definitely failed the test. I stood in the open, asking to be blown up and, although I appeared calm, my mind was panicking thinking, "when the hell can I cross the street?"