At 7:55 p.m. Wednesday, American University was put on lockdown. There was a suspected shooter on campus.

I was in our student center, studying for an exam set to begin in 15 minutes, when an alarm went off. I was with a group of about seven friends; nobody knew what it meant. Then we all got a text from our public safety office:

“AU Alert: man with gun seen on campus. Campus is in lockdown. Shelter in place. More info to follow.”

We laughed nervously, thinking at first that this was a drill or even a joke. But it soon became clear that it was real. I scanned our surroundings: a lot of windows, doors that didn’t lock, a large, open floor plan with few places to hide.

“Let’s go upstairs,” I said. “There’s a room that locks.”

That was enough for my friends, and we all went, speeding up as we approached the door. I touched my ID to the scanner and pushed. A table had already been shoved against the door. My stomach dropped, but we were able to force our way in. The lights were out, and about 15 people were huddled on the floor. We got low to the ground and kept silent.

I couldn’t stop shaking. I texted my friends, but the words wouldn’t come out right. I typed over and over, reassuring those who had checked in on me. I crouched below the window line, stealing quick looks outside whenever I could muster the courage.

Finally, an hour and a half after it began, we received this message: “All Clear. Campus is all clear, the lockdown is lifted. Campus may resume normal operations. Suspect is in custody.”

So, believe it or not, I went and I took my final exam. I was still numb. I was asked about what I had learned the past semester in my class, and my mind drew a blank.

Now, of course, we know this was just a false alarm. An off-duty police officer was wearing his gun holster on a university shuttle bus. Some might say the campus overreacted, that the lockdown was excessive and the worry all for nothing. But was it? A man believed to have a gun was seen on campus. We know all too well how that can turn out.

I still can’t believe this happened. I was not and am not okay. While my roommate and I were walking home together, someone honked a horn, and we both gasped and stopped in our tracks. We got back to our apartment and opened a bottle of wine. Our neighbors came home, and I froze at the sound of people on the other side of a locked door. I don’t think I’ll be over this for a while.

And should I? How can a school go on lockdown for an hour and a half and then simply return to “normal” operations? What does normal mean when you’ve been huddling next to friends and strangers, going over in your head what you will do if a gunman comes bursting through the door? For an hour and a half, as helicopter spotlights swept across the room, my only thoughts were of survival.

Navy Yard. Newtown. Aurora. Tucson. Fort Hood. Virginia Tech. Columbine. Too many from even just my own lifetime to list. Why is this something that we accept? Enough is enough. This is not a culture anyone should have to live in. Let’s finally do something about it.

The writer is a student at American University.