The chairman of the tribunal, Mr Justice Barr, has been urged to avoid applying "the most perfect of hindsight" when assessing the actions of gardaí during the siege at Abbeylara.
Mr Cian Ferriter, for the Garda Commissioner and other senior gardaí, made the request when he and his colleague, Mr Diarmuid McGuinness SC, began their final submission to the tribunal yesterday.
The tribunal is investigating the shooting dead of John Carthy by members of the Garda's Emergency Response Unit after a day-long stand-off at his home in Abbeylara on April 20th, 2000.
The tribunal hearings should conclude before Christmas, with Mr Justice Barr's report expected next spring.
Mr Ferriter urged the tribunal chairman to avoid applying an unrealistically demanding level of assessment to the actions of the gardaí. They had found themselves in an extraordinary, unprecedented and often dangerous incident, and their actions should be judged on what they knew at the time.
He asked Mr Justice Barr to "try to inhabit the physical and mental geography of the gardaí at the scene".
Earlier, Mr Diarmuid McGuinness SC said the tribunal chairman should not have reached conclusions on any issue yet. "If you have made up your mind, you should unmake it, and declare yourself open-minded on all the issues," he said. "You should not have put pen to paper yet. If you have, you should scratch out what you have written."
It was Mr Justice Barr's "bounden duty" to give full consideration to all the submissions so he "should be equally and genuinely anxious to hear what all parties have to say and not merely desirous of getting it over with".
Mr McGuinness also asked the chairman to view the events at Abbeylara in the general policing context in Ireland. He pointed to a number of factors including the very low frequency of siege-type incidents and the rare discharge of weapons by gardaí.
From January 1st, 1998, to May 2004, some 63 shots were discharged by gardaí in 13 incidents. Excluding Abbeylara, two people were killed in these incidents: one was a criminal suspect in the course of an armed robbery while the other was the accidental death of a garda, caused by a bullet that ricocheted.
Mr McGuinness said the death of Mr Carthy was "very much regretted" by An Garda Síochána. The Garda Commissioner and his senior officers fully recognised "the grief and the extent of the suffering of Mrs Carthy and Ms Marie Carthy and their extended family".
It had always been hoped that the siege would end without loss of life or serious injury to anyone involved. "It is hoped that both the tribunal and the Carthy family would fully recognise that and accept the bona fide motivation of those members of the force concerned in the events of the 19th and 20th of April, 2000," Mr McGuinness said.
The Garda Commissioner, Mr Noel Conroy, joined in the wish of Ms Marie Carthy that "the outcome of the work of the tribunal may contribute to a police force which will, if at all possible, be able to take steps to avoid, in the future, the type of unfortunate and undesired death that her brother met".
The tribunal earlier heard final submissions from counsel for RTÉ and from Mr Carthy's psychiatrist, Dr David Shanley.
Ms Oonagh McCrann SC, for the psychiatrist, said Dr Shanley hoped the tribunal's work would result in the adopting of new and improved procedures that would lessen the possibility of such an event happening again.
He also hoped it would result in a diminution of the stigma traditionally associated with psychiatric illness, Ms McCrann said.
