"He said, 'You know, something we never do enough is tell each other that we love each other,'" his friend Brandon Wolf told CNN's Alisyn Camerota.
Wolf told Leinonen that he loved him back, and they went inside to dance. Later, while Wolf and friend Eric Borrero took a bathroom break, the gunshots that killed 49 people
began. Leinonen and his boyfriend Juan Guerrero were among the victims
Wolf, Borrero and a group of other people hiding in a bathroom joined hands and made a run for it. They got out but stopped two blocks away, realizing Leinonen and Guerrero were still inside.
"I wanted to go back so bad," Wolf said through tears. "It was too late by then."
Then there was an agonizing period of not know what happened to their friends. They say at first they assumed Guerrero was okay because someone saw him being sent to the hospital. And despite no word on Leinonen's whereabouts, they held out hope that he was still alive.
"One minute you're telling yourself, 'I have to come to terms that my best friend is gone,'" Wolf said. "And then the next minute you're telling yourself, 'But he could be there.'"
There was a lot of chatter around Leinonen, whose mother gripped the country with a series of emotional interviews
. When his and Guerrero's deaths were confirmed, their families announced plans to hold a joint funeral
for them. That is a small comfort to their friends, who say they're glad at least that one does not have to live without the other.
The group talked about attending a vigil where a Muslim woman came and prayed for Wolf and Borrero at a spot set aside for their two friends. Wolf said it was a powerful reminder that no matter what group we belong to, humans are all one big family.
Going forward, Leinonen and Guerrero's friends are hoping to see ongoing conversations about both guns and hate.
"If I want to see anything change, it's that people get over themselves and start loving each other," Wolf said.