On June 27, 53 migrants lost their lives inside that 18-wheeler, ultimately succumbing to the Texas summer heat. It was the single deadliest smuggling case in U.S. history.
Gomez was one of the few who made it out alive.
He spoke exclusively with ABC News, the first American network to get an on-camera interview with a survivor, sharing a harrowing glimpse at what happened inside that trailer.
Gomez's journey started in his native Guatemala. He comes from Huehuetenango, a city near the Mexico-Guatemala border where 73% of people live in poverty.
Back in his hometown, a regular day for Gomez meant working in the fields, sowing corn and beans.
Gomez made the journey to the U.S. "because of the lack of opportunities in my country," he told ABC News in Spanish. "I wanted my kids to have opportunities."
Gomez planned to take both of his children and his wife with him. But at the last minute, Gomez decided to make the journey alone, using his life savings and asking for loans in order to pay for the trip.
"It was like $1,500 for taking you to Mexico and then in Rio Bravo; they charge you per segment," he said. "In total it was like $8,000."
During the journey, Gomez said the migrants were placed in a "long truck" used for transporting animals. At one point, they were then held in a basement for days with limited access to water and with only bread to eat.
The "coyotes" — or smugglers — also confiscated the migrants' phones so they couldn't communicate with or send their location to anyone.
But at the time, Gomez said it all felt worth it when they finally reached the border in Rio Grande City, seeing the U.S. on the other side, within reach.
"I think it's something that all immigrants feel," he said. "Our dream, and I know I'm going to get there."
However, few in Gomez's group would ultimately make it to their destination.
"Once they put us inside the trailer, we had to wait like 10 minutes. Then more people came, and in total we were like 65 or 70 people in that trailer," he said.
Two hours later, the suffocating heat inside the trailer became "unbearable," Gomez said.
"We started banging at the door, and other people started banging at the door so they would let us out," he recounted. "The driver could hear us, and he said 'no' and told us to shut up and started insulting us … And then people started crying."
Gomez said the people around him began to panic, dying one by one.
"The person next to me told me 'I'm going to die.' And I told him, 'No, you're not going to die, we're going to make it.' 'No, I can't take it anymore,'" Gomez recounted. "And he started shaking. He trembled once, then again, then again. And after the fourth or fifth time, he died."
"And then the same happened to another person, and then another," he continued.
At some point, Gomez said he remembers the truck stopped. Cries for help ensued, but no one answered.
"I wish I could have knocked those doors down and saved their lives," Gomez said, referring to the truck's locked trailer.
The police eventually found and opened the doors to the trailer, taking the survivors to the hospital. By then, Gomez said he couldn't even stand.
"At the hospital, I started to regain consciousness and I realized what had happened," he said. "It was so painful, realizing what had happened to my friends, who had big dreams."
"Today, they're not here anymore," he continued. "It's hard to explain, because one day you're talking to someone, we are on this journey together, and the next day… they're gone. And watching them die."
Fifty-three people, many of them just teenagers, lost their lives that day.
The Biden administration is making a concerted effort to crack down on human smuggling with its "Counter Human Smuggler Campaign," which the Department of Homeland Security claims is designed to disrupt and dismantle human smuggling networks.
In less than six months, DHS says it has arrested 5,000 human smugglers.
Among those are the trailer driver and three others who are suspected of being connected to the vehicle Gomez traveled in. They have all pleaded not guilty.
Now living in San Francisco with his brother, Gomez said he is still trying to pick up the pieces.
"Thank God, they treated me well, and told me I was a survivor and that many people died," he said. "And I'm still here until this day. And they are letting me stay for a year to see if I can get a visa."
Gomez said there is a "50-50 chance" he will be able to reunite with his family.
Gomez said he hopes his experience will help people understand the reasons that drove his decision to make the perilous journey and the abuses some migrants have to endure to seek opportunity and refuge in the U.S.
"I think the sun comes out for everyone. Not just for a few. And I think we should be treated like human beings. That's what we are," he said. "I wish that opportunities were given to people that want a better life."
-ABC News' Isabella Rolz contributed to this report.