The biggest beach party in the world was going on around him, but lifeguard Cabo Guido Serafini was looking at the woman writhing on the sand.
She seemed like she was in convulsions, with her eyes rolling back in her head and a stream of what seemed like nonsense coming out of her mouth. More alarmingly, she was right on the edge of the water, and the sea was tumultuous. He quickly got to work, crouching down to see if he could revive her.
"Then this man approached me and started telling me off. 'Please, don't touch her,' he kept saying. 'She's in the middle of being possessed by a saint,' " Serafini recounted. He had inadvertently interrupted a ritual in the Candomble religion in which spirit possession is a common component.
Just another New Year's Eve for Rio de Janeiro's lifeguards.
"Such crazy things happen to us on the beach," Serafini said with a laugh.
I met him and some more of the 45-strong lifeguard corps right on the edge of Copacabana Beach, where the group was preparing this year's big event.
While the rest of the world counts New Year's Eve as one of the best nights of the year, Rio's lifeguards acknowledge that for them it ranks among the worst.
Two million people descend on the beach to party and watch the fireworks — which would be fine if they stayed on the sand. But Rio de Janeiro has some particular rituals that go along with celebrating at midnight.
People dress in white and toss flowers as offerings into the sea. To bring luck in the coming year, tradition holds, you have to jump over seven waves.
"Except people get pretty drunk," explained Fernando Santos, the lifeguard commander. "There's plenty of alcohol consumption and people are full of food, then they go into the water and pass out."
It's not much fun pulling them out, he noted blandly. Santos said he will be on the beach base overseeing operations for 24 hours — from dawn to dawn — "basically without any sleep. You have to have a lot of strength, energy, to keep up the work."
On an average day in Rio, the lifeguards are some of the most active in the world. And these days they have high-tech toys to aid them, like drones and jet skis.
But on New Year's Eve, it's dark and chaotic and crowded. So lifeguard Gustavo Melich says he relies on his "sixth sense." Last year, he felt he just had to do one more sweep.
"The fireworks had taken place already, people were heading back home, and then I made a dive. All of a sudden I saw a hat, floating in the water, a Panama hat. When I grabbed at the hat I discovered a person. The guy was face down in the water. He would probably have died," Melich said. "He was lucky that I was in the right place at the right time, so I could rescue him."
Melich and Serafini haven't had a New Year's Eve at home with their families for six years because it's their busiest night at work.
Melich says for the most part they don't mind.
"The feeling of having saved someone's life, regardless of the time of the year, brings you a lot of satisfaction," he said. "I feel I am earning my stay on this planet; it is a big feeling that comforts us."
Except Serafini says no one ever really thanks them.
Statistics show young males are the ones who most often need to be rescued, and Serafini says they get embarrassed and run off after they are pulled out of the water.
"Nobody saves lives like [we do] here in Rio," Serafini said. "Sometimes just someone shaking our hand out of recognition for saving a life is the best feeling any life guard can have." But it rarely happens, he added.
Melich was asked to recount the strangest thing he's seen on the beach.
"I often see men use their girlfriend as a flotation device when they are drowning. She ends up under water, and because the guy is stronger she's in a lot worse shape," Melich said.
Then he added: "I have seen many relationships end right on the beach after a rescue."