(CNN) -- A deadly 2009 "sweat lodge" retreat in Arizona left participants so sickened that the scene resembled "a battleground" with people vomiting, foaming at the mouth and with their eyes nearly popping out, according to one survivor who testified Thursday.
"I saw people agonizing," said Lou Caci, a participant from Winnipeg, Manitoba. "It looked like a battle ground. People are just laying there."
Caci, who earlier testified he fell at one point and badly burned his arm on the heated rocks, continued his testimony Thursday in the trial of self-help guru James Arthur Ray. Ray is accused of manslaughter in the deaths of three persons at his October 2009 "Spiritual Warrior" retreat in the desert.
Killed were Kirby Brown, 38, of Westtown, New York; James Shore, 40, of Milwaukee, Wisconsin; and volunteer Lizbeth Marie Neuman, 49, of Prior Lake, Minnesota. At least 15 others who took part in the sweat lodge ceremony became ill, but more than 40 others were uninjured, and defense lawyers have argued that the deaths were accidental.
James Ray's attorneys have also argued that exposure to an unknown toxin, perhaps a pesticide, could have caused the fatalities.
The event participants paid up to $10,000 to seek "new areas of consciousness," according to this week's testimony.
The lodge -- made of willow trees and branches, and covered with tarpaulins and blankets -- was heated to perilously high temperatures, causing the participants to suffer dehydration and heatstroke.
The sweat lodge ceremony consisted of eight rounds, with each round lasting 10 to 15 minutes. While they were not prevented from leaving, participants have said they were encouraged to wait until the breaks between rounds.
Under questioning by the prosecution, Caci recounted how he re-entered the sweat lodge and came across one participant, Neuman. She was among those who died.
"Seeing the way Liz was I knew there was something terribly wrong. I was a bit apprehensive about being back in there just because of the pain I had in my arm. We finished the last ceremony and I was more focused on staying awake," Caci told the court.
"She was a heavy-set woman and I couldn't quite get her out. So a fellow named Randy helped me," Caci said. "I was lifting her little by little. She was heavy. Randy was helping me. We would go, 'One, two, three' -- and we would lift. I think her face dragged on the ground a little bit, but we helped her out."