A prisoner who died after falling from a police custody van with a faulty cell door had probably attempted a spur-of-the-moment escape bid, his father has told an inquest.
Paul Somerville (21) died in hospital three days after sustaining serious head injuries in the incident in his home town of Maghera in January last year.
The trainee electrician somehow exited the back of the police's adapted Volkswagen van minutes after two PSNI officers picked him up at his house on Crewe Road to transport him back to Maghaberry prison.
The drugs offender had been recalled to custody by parole authorities for a breach of a release licence.
On the first day of an inquest hearing in Ballymena, Northern Ireland's Senior Coroner John Leckey heard that the internal door of the single cell in the rear of the PSNI custody vehicle was subsequently found to be faulty.
The malfunction had not been identified prior to the incident, despite the locks being examined by mechanics days earlier at the request of a concerned officer.
While this erratic locking mechanism likely enabled Mr Somerville to get out of the cell, Mr Leckey was told that the prisoner, who police witnesses said had a history of drug use and violent encounters with officers, still had to get through a roll up external door to escape the vehicle.
The offender's parents Gwen and Desmond were both asked if they accepted that their son would have had to perform a deliberate act to exit the van, even if the internal cell door lock had broken.
They both acknowledged the evidence pointed to this.
"I would think it was a spur-of-the-moment thing, probably overcome by thought of going back (to prison)," said Mr Somerville.
Mrs Somerville insisted her son was calm when officers came to the house to collect him.
Mr Leckey had asked if her son had the potential to "fly off the handle". "He would be impulsive at times," she replied.
Mr Leckey explained that expert examinations had found an "erratic fault" that meant the lock on the cell door sometimes worked and sometimes did not.
He said that would have given a "false sense of reassurance" to anyone who had tested the lock and found it to be functioning.
Dr David McNeill, who was working at medical centre close to the scene of the fatal incident, rushed to Mr Somerville's aid.
He questioned the input of police officers in the immediate aftermath, claiming it took too long for him to be told the facts.
Having initially thought he was dealing with a collapse or fitting incident, he had moved Mr Somerville prior to being given the information by police.
"I probably wouldn't have moved the patient if I had known the patient had fallen from a moving vehicle," he said, explaining the potential of spinal injury.
With concerns about what had unfolded, he told the court how he had warned the police officer.
"I remember telling the officer that he had better have dotted the Is and crossed the Ts because this didn't look good," he said.
The doctor added: "I did not think that Mr Somerville would survive and I know he was in the custody of police at the time, so I knew the gravity of situation for both him and the police."
Michael Egan, representing the officers who were in the custody van during the incident, claimed there was a sense of confusion as to what had happened at the time.
While Mr Egan was appearing on behalf of the two officers, the PSNI was not legally represented at the hearing. Mr Leckey said he considered that "unusual and surprising".
The inquest continues.