At 5 a.m., my alarm erupted with its usual blend of static and pop music, the start of another day of work at the Washington Navy Yard. I was in the car at 5:15 and pulled through the gates to the base at 6:15, handing my ID card to one of the police officers at the gate as I always do. Within a few hours, a dozen people would be dead.

I’m a civilian contractor for the Navy, and in the five weeks I’ve been assigned to work at the Navy Yard in declassification, I have come to love the base. It’s a quiet, small-town alcove in the midst of the city, and it has gorgeous views of the river, a relaxed atmosphere, and a Dunkin’ Donuts just steps from my desk. There are always military personnel around, but, to me, it seems as though the base is mostly civilian — a bunch of lucky professionals in D.C.’s hidden, suburban-like Navy base. We civilians can enjoy most of what the base has, including the convenience store, bar and some of the best crab soup I have ever had. The base’s many monuments and museums make it a perfect place to take a long walk. During the summer, there were even base-wide ice cream socials every other Thursday. And a few days ago, on 9/11, the Navy held a gun salute at the moment when the first plane hit the first tower. Working here feels like being a part of a unique, thriving community.

About 8:30 Monday morning, the base-wide broadcast system announced a lockdown and instructed us to shelter in place. From our third floor window, we saw SWAT teams clinically moving up the street with their weapons drawn, but we heard only rumors for the next two hours. We heard some radio and Twitter news, and a bit of Internet news, and lots of people were getting text messages from friends and family. We were all just shouting out the latest information we had. The number of shooters kept increasing and so did the number of victims. Then we heard that some victims had died, then that an admiral had been shot. One of my co-workers saw a woman walking up the street bleeding from her head. We tried to work but couldn’t focus.

[For up to the minute information about the shooting, check The Post’s live blog .]

When the lockdown was first announced, we rolled our eyes at the man in our outer office who told us to stay away from the windows for fear of becoming a target. He seemed to be having a panic attack. It wasn’t obvious yet that something major was happening. It seemed far more likely that this was a drill or some kind of mistake. As we learned more, we stayed safe in our office, behind two secure doors that require pass codes for entry. Sitting with my friends, it almost felt safe. About 10:30, we were moved to the basement of our building, into a small library. They counted us as we went by. I was No. 70. We huddled together in the back of the room, sitting on the floor. An older man near us observed that being in that room on the ground level probably made us less safe than if we had stayed where we were.

Map: See the scene of the Navy Yard shootings and nearby closures.

As we huddled on the floor, cramping up, an alarm went off. It took us a moment to realize that it was the library’s security system going off erroneously. We were a bit tense but mostly calm. A few minutes passed, and they finally made an announcement. A woman near me wouldn’t stop talking so we could hear. I shushed her more forcefully than I would have thought possible, and she silenced herself immediately. My Marine colonel grandfather would have been proud. Then, it happened.

“Hands up! Get your hands up! Everybody to the back of the room!” I jolted off my rear into a crouched position and looked around. I quickly realized that I was in the back of the room already. Somehow, that didn’t make me feel any better. I unlocked my phone to call my wife. Another man’s phone rang in that moment of silence, and everyone glared at him, like it was his fault. We couldn’t hear what was going on in the hallway where the yelling had come from, but it seemed to have been just a misunderstanding. No one ever explained what happened.

A few minutes later, someone asked whether anyone had a medical condition or needed to use the bathroom. They started taking us to the bathroom in groups of two. Someone found candy and passed it around. I got up and kicked myself for not thinking more about the room when I had walked into it. I took that time to note the exact position of the door, the windows, and something I could use as a weapon. The best possible weapon was a book, a big one called “Congress and the Nation.” Even in that moment, I still smiled at the thought of killing a terrorist with “Congress and the Nation.” A few minutes later, they moved us to another building. I grabbed my co-workers and said that I thought we should stick together and that we should not be at the beginning or the end of the line, just in case. We got outside and jogged to the food court, where there were bathrooms and hundreds of other confused people.

And now I’m preparing to leave the Navy Yard, still confused, after a very different day than I imagined having when I left home at 5 in the morning.

Ryan is a civilian contractor for the Navy.