"They become very excited and agitated. It is more likely that this attack happened because this dog had taken cocaine."
The BBC crew were at Perivoitos' home while filming Drugs Map of Great Britain when he began to have a seizure and the staffordshire bull terrier attacked him.
Pathologist Julie Higgins said Perivoitos' body "included injuries to the neck and face, with extensive haemorrhaging, and the larynx was crushed".
Programme producer Joshua Haddow managed to wrestle Major off his owner, but it was too late.
The inquest heard that Perivoitos died because of injuries inflicted by the dog.
Senior coroner Andrew Walker noted that the victim had taken cocaine before the attack.
"It is likely that he was experiencing an epileptic shock, which caused the dog to nip his face before biting his neck. The film crew telephoned an ambulance while attempting to get the dog off Mr Perivoitos," he said.
"It is likely that the dog had consumed cocaine by eating it and it is likely that this was an additional factor in the dog's behaviour. Mr Perivoitos suffered serious injuries and was taken to a major trauma hospital, and died shortly after midnight."