GéraldFontaine was working at Ferme Reine de la Paix, a country house near Drummondville in the Eastern Townships, the day Lavigne died in July 2011.,
The detox therapy session was part of a seminar called "Dying in Consciousness" led by a self-styled Quebec therapist.
Lavigne and eight other participants were covered in mud, wrapped in plastic and blankets and spent nine hours lying with their heads in boxes while being encouraged to hyperventilate.
Fontaine said he was actually more concerned with another client because, he said, she seemed out of sorts. That client survived after being treated in hospital, but Lavigne did not.
Lavigne was eventually taken to hospital unconscious by ambulance, with a body temperature of 40.5 C. Normal human body temperature is 37 C.
Lavigne, a 35-year-old mother of two, died hours later of hyperthermia — a medical emergency caused by failed thermoregulation, when the body produces or absorbs more heat than it can dissipate. Lavigne’s coroner’s report said she literally cooked to death.
The mother of Lavigne’s husband has been attending the trial. Ginette Naud said her son hasn’t been able to sit through the testimony.
“He said, ‘I can’t go inside because I just want to cry each time,’” Naud said.
Fontaine, along with his co-workers Gabrielle Fréchette and Ginette Duclos were charged with criminal negligence causing death and criminal negligence causing injury.
Their defence lawyers argued Wednesday afternoon that Lavigne was responsible for her own death. One lawyer said Lavigne was an adult, and if she wasn’t feeling well she should have walked away.
The trial resumes Dec. 8.