Moments after the explosions, I turned to Twitter to alert people to what happened.

When I heard the first boom, I thought maybe it was a celebratory cannon. Boston adheres to a lot of odd colonial traditions that Midwesterners like me just don’t understand. It was Patriots’ Day after all.  As I scanned the crowd, I could tell others were equally perplexed. Seconds later, I heard and felt a second, louder explosion shake the ground and reverberate in my chest.

Then I didn’t think. I just ran.

Unable to text or make phone calls, I continued to tweet.

As I sprinted through the Lord & Taylor store on Boylston Street, instinct told me I was fleeing from danger, but I had no idea I was escaping a gruesome terrorist attack that would maim and kill Boston Marathon spectators, forever changing the joyous event. I left the scene with an overwhelming sense of disbelief, which persists four days later as I sit glued to the constant news coverage of the manhunt for the second suspect.

What I cannot shake is a feeling I am sure fellow Boston residents and their families share. When disaster strikes so close to home, it makes you question, “What if?” You can drive yourself crazy coming up with endless scenarios in which it could have been you or someone you love who was hurt. You know it’s not a productive thought, but it’s impossible not to indulge.

What if I had not been exactly where I was when I was? I had been slowly making my way up to the finish in the moments leading up to the blasts. I reached Mile 26 and paused to take some pictures near the Prudential Center. As I pushed forward, the crowd got thicker and the sidewalk became nearly impossible to navigate. Frustration and impatience lead me to the doors of the Lord & Taylor department store.

Where I ended up shortly after escaping.

I was looking for a shortcut through the back of the store so I could loop around and get to the finish line faster. The first bomb went off just as I got to the doors, giving me a clear escape route once the second bomb detonated almost directly across the street. Although I feel incredibly lucky to have made it out unharmed without seeing any grisly images, I still keep asking, what if?

What if I had been on the other side of the street? What if I had made it all the way to the finish line? What if I had not decided to cut through the store?

Would I have been stuck on the sidewalk? Would I have seen horrors that would haunt me forever? Would I still be alive?

The “what ifs” temporarily subsided until this morning, when I learned of a violent shootout with the suspects in Watertown, a suburb two miles from my neighborhood, Brighton. The fear and confusion from Monday resurfaced, even though I was further from harm than the first time.

What if the suspects had made it to Brighton instead? What if this had happened yesterday when my boyfriend was waiting outside in Watertown for the second of two buses he takes to get to Brandeis University where he attends grad school?

What if, what if, what if?

It’s 8 p.m. in Boston as I write this, and police seem to have the suspect cornered, but it’s clear that no one really knows what’s going on. Even though it feels like things are wrapping up, the uncertainty–the “what ifs” are eating me alive and driving me—and probably everyone else—insane. I do not blame law enforcement. I know they’re doing the best they can. I just wish this awful feeling in my gut would settle.

Holly Hartung (@frauhartung) is a Wisconsin native and recent graduate of UW-Madison who moved to Boston last September. To listen to audio of her interview with a Madison news channel shortly after Monday’s bombing, click here.