Editor’s Note: Randy Jacobus, 48, is a hedge-fund manager from Eden Prairie, Minn., and a long-time member of Life Time Fitness. A runner since high school, he completed three marathons before qualifying for the Boston Marathon in 2011. He had planned to run the world-famous course in 2012, but deferred to 2013 due to the heat (“Little did I know,” he says). The 2013 Boston Marathon was meant to be his “bucket list” race — the last one. Given the chain of events that played out just minutes after he crossed the finish line, however, Jacobus is hoping to run it again in 2014 or 2015 to show his support of Boston and its phenomenal tradition. Here, Jacobus shares his first-hand account of his experience.

The van is late. Short, nervous chitchats. Another drink of water. Nibble on a banana.  Are we going to make it in time? Finally, the van arrives and in we squeeze. On the road, our driver demands introductions, a tradition of his.  “North Carolina, Quebec, New York, Minnesota, Tennessee …” We are from all parts, some making second trips, others their first. We’re all anxious.

The traffic looks to be backed up for miles. Narrow roads and only one way to go — how are we going to make it? Proud local cops tersely deny access and turn cars away. Our driver rolls down his window, and in his think Boston accent says, “Runnas, I’ve got Runnas.” A secret code. The officer smiles, moves the barricade and ushers us to a clear lane straight to Athlete’s Village and the starting line of the 2013 Boston Marathon.

I’m shivering in the breeze, not sure if it’s the temperature or nerves, lost amongst the runners and not sure where to go. They’re tall, short; some are sitting, some standing; most with a predetermined plan, a ritual. They have done this many times: first the socks, then the shoes, tying them just right. Sunscreen, energy gels, sunglasses, time goals written on their arms. They speak in many languages: French, Spanish, Japanese. Some are old acquaintances reuniting; some are with bigger groups; others alone. All with strong calves and legs.

Trying to fit in, I removed my sweatshirt, stretched my tight hamstring, and rocked my calves back and forth against the curb, taking in all the sights and wishing I had my cell phone to take a few pictures. I had never seen so many yellow buses.  Surely this middle school never intended to have 27,000 runners stretching and napping on every inch of its grounds. I handed my bag to the volunteer. “It will be there,” she said, “just pick it up at the finish line.” She then pointed me in the direction of the starting line, and I began the slow jog to the starting area, nervous about what lay ahead.

Small houses lined the narrow street to the corrals. One with a sign that read “Free Wares” received the most attention: Free bib pins, band-aids, hair clips — you name it, you could find it at this house, and it was free. The porta potties were on the left side of the road in a parking lot, hundreds of them. The far ones had the least activity, so that is where I headed one last time before the start.

I could see corral No. 9 just down the hill, where runners were waiting nervously for the gun to sound and the official start of Wave 1. There were nine corrals, each holding 1,000 runners. Security carefully monitored the bib colors and who they let down to the starting area.  At 10 am, the gun sounded and the first wave was off. Wave two next, and security checked the bibs, turning the blue bibs away harshly, “Only red and white!” I headed for corral number one.

We stood idly, a little more nervous chitchat and some stretching. Then the gun sounded and we were off. Winding down we went, the Hopkington roads narrow and hilly. I was always watching my step: We were shoulder to shoulder; there was no room for error. Sharply down and faster, keeping a 7-minute pace felt easy. Then a sharp upturn and the pace slowed. Back and forth this went as we wound thru Ashland, local support waving their traditional signs and playing their motivational music. It was mostly older, traditional, and family support along these parts — they were proud to be our host.

The first 10k came and went, and I was running a little faster than my targeted pace. The conversations around me started to percolate as the flatter terrain encouraged a rhythm. Some runners reunited, others meeting for the first time. Two girls from Wisconsin connect over their similarities: both getting married in June, both with fiancés who did not run, both high school sweethearts.  “Go Alaska!” “Go Canada!” “Go Russia!”  I was surrounded by an international melting pot. Running side by side, I found a partner that I could stride with and forget about the miles ahead.

We ran uphill into Natick and then downhill into Wellesley, passed the halfway point. A glance at the watch and I was a little behind schedule, but not much. Hundreds of college girls lined the street, begging for kisses from all the sweaty men. “Kiss me, I am a chemistry major!” “I run better naked!”  These are the Wellesley Girls and they seem to go on forever. A good distraction, no doubt, but soon there’s another sharp downhill turn and mile 16 was in sight. My quads ached and I feared more down hills. Runners started passing me.

My legs felt heavy, but there were only 10 miles to go.  Uphill we ran toward Brookline. Another hill and more runners went around me like Billy goats. Was my pace slowing that much? Into Newton we ran, where the Boston College fraternity boys are loud. “Colorado, pick it up, you can do it,” they scream. This is Heart Break Hill, the final and toughest climb at mile 21. I counted my footsteps to take my mind off the endless climb, and I didn’t look up for fear of giving up. “You can do it Colorado!” I made it to the top, but my pace … Why were they passing me?

Five miles to go and it’s all downhill. We entered Brookline and Boston proper; more college kids lined the street and the crowds seemed to be growing. This should have been the easy part, with a gradual downhill all the way to the finish, but it felt like a knife was piercing my right side. I couldn’t stand tall and I couldn’t lift my right leg. I slowly moved to the side — the side without the jeering students: “Come on Colorado, you are almost there!” I walked next to the T-line where security guards lined the street, protecting the runners from veering onto the tracks and keeping spectators from getting too close. I wanted to run but couldn’t and a few others joined me on my walk. But they walked a lot faster.

Mile 23 came and went, and yet I was still pain. “Colorado, Colorado, Colorado …” they chanted and I tried to get going again. My goal at this point was to finish. One foot in front of another, I counted my strides, just get to mile 24, and though more people passed, I was still moving. The streets were lined with supportive crowds who encourage and pushed.

Mile 25: one more mile, an eternity. More crowds, more support.  Turning the corner onto Boylston Street, I saw the finish line and could hear the crowd’s support. Other runners in similar situations, plodded next to me, and we crossed the rubber marking the finish. We stopped our watches — 3 hours and 54 minutes later.

I was disappointed with my time, but relieved it was over. My legs were sore and numb, and my energy was sapped, but there were smiling faces all around. Amidst hugs and congratulations, we moved slowly through the finishing corral to gather water, refreshments, snacks, medals and, most importantly, a blanket to warm us from the chilly breeze that blew in our face. I wanted to get off my feet. I was too tired to find my bag and moved quickly to the right, through the crowded family greeting area, to the first bus heading back to Hopkington. The buses were warm, and I was cold and tired. A few other runners had similar ideas.

The first blast startled us all. “What was that?” we all muttered simultaneously. As we sat, the second blast hit and shook the bus. The driver was alarmed. “What the …?” he asks. We sat quietly, wondering, hoping the sounds were not what we thought they were. The driver’s radio crackled and what we all knew was confirmed: two bomb blasts one block away, the hotel blocking our view and sheltering us from the chaos. Spectators ran by our bus, one with blood on his back: “Get to Mass General, follow me, I am not a crazy! Two bombs, hundreds are bleeding. We need to get to Mass General to give blood. PLEASE, follow me!” And people did.

Our bus was full of anxious runners. Concerned about additional bomb blasts, some asked the driver to depart. He snapped back patriotically, “We are staying put in case they need us to transport the injured. Sit down!” A few minutes later, the radio crackled again and the driver slammed the door shut. “Sit down!” and we lurched forward. Word from his supervisor to get us out of the area, and quickly, had come.

It was solemn; not much talking, though lots of whispers. The thoughts of bombs and injuries drowned the feelings of accomplishment; months of training and sacrifice stolen by cowards hiding in the shadows. There was no talk of the day’s feat: Only concerns for those still on the course or for friends still missing.

As we headed out of the city, cell service resumed and phones started buzzing. Tearful runners spoke to their loved ones: “Yes, we are OK.”  “I have not heard. Call me if you hear from her.” Mark from Fort Worth sat next to me and offered me his phone to call my wife. “Yes, I am OK. I’m on the bus back to Hopkington, and will call when I get back to hotel. Love you.”

Mark offered to drive me back to Milford and to my hotel. I turned and watched the runners exit the bus as he looked for his keys: Some limped, some shuffled, some avoided the stairs. One thing was for sure — they would be back next year. This was the Boston Marathon and these were “Runnas.”