The prosecution says a former Canadian soldier neglected his duty by failing to take the ammunition out of his weapon before the fatal shooting of a fellow reservist in Afghanistan more than four years ago.
Matthew Wilcox has told a court martial he fired his weapon instinctively when he saw a gun pointed at his head in his tent at Kandahar Airfield on March 6, 2007.
He has also said the only other person inside the tent had to be his best friend, Cpl. Kevin Megeney — the 25-year-old man he is accused of fatally shooting.
Prosecutor Cmdr. Rob Fetterly argued in his final submission on Friday that Wilcox had many chances to safely unload his gun before entering his tent.
"He chose to ignore this duty for the sake of convenience," he said, adding that Mr. Wilcox admitted to leaving the magazine in his weapon because he was too busy carrying his gear.
The prosecution has alleged that the pair were playing a game of quick draw.
Mr. Wilcox, 26, who is facing a second court martial in the case, has denied telling anyone that the two infantrymen from Nova Scotia were playing a game of quick draw when his gun went off.
The ex-reservist from Glace Bay has told the military court he knowingly failed to remove a loaded magazine from his 9-mm Browning pistol before entering the tent he shared with Mr. Megeney, who was from Stellarton.
The former corporal with the 2nd Battalion, Nova Scotia Highlanders said he left the magazine in the semi-automatic weapon because he was too busy carrying his gear after completing a long shift guarding the camp's main gate.
Mr. Wilcox has pleaded not guilty to criminal negligence causing death and negligent performance of a military duty.
Fetterly said Mr. Wilcox also failed to properly assess the alleged threat in his tent when he claimed to see a gun pointed at his head.
"He knowingly keeps his weapon loaded and consciously fails to perform any threat assessment," he said.
The prosecution argued it was unlikely anyone other than the Mr. Megeney would be in the tent they had shared for more than 80 days.
Mr. Wilcox was sentenced to four years in prison and ejected from the military after he was found guilty of the two offences following the first court martial in 2009.
That verdict was set aside last year and a new trial ordered after Mr. Wilcox's lawyers argued the makeup of the military jury was unfair. The panel had four members instead of the usual five because one was excused due to a conflict with work.
The second court martial started in April.