Paul Levy, vice-president of airport operations, said it's now known that Robert Dziekanski got off a flight and passed through initial customs screening at about 4 p.m. on Oct. 13.
But he didn't show up in the customs hall until 10:30 p.m.
He cleared customs and immigration around 12:30 a.m. Sunday and just over an hour later, was zapped with the Taser and lay on the floor dying.
That means there are still several hours unaccounted for before Dziekanski finally went through the immigration process.
He was unable to speak English, had just completed his first flight ever and had given away his last packages of cigarettes before embarking on almost 24 hours of travel.
"He, for whatever reason, decided to stay inside that customs hall around the (luggage) carousels for over six hours,'' Levy said.
Levy said airport staff are not responsible for that area, so he doesn't know why no one noticed Dziekanski loitering in the baggage area for so long.
"During that time when he was in that area, there would have been over 4,100 passengers that would have transited through there,'' he said.
While Dziekanski waited, his mother Zofia Cisowski also waited, but outside in the public area.
A lawyer for Cisowski has said the woman, who worked two jobs for years to bring Dziekanski to Canada, told her son to wait for her by the baggage carousels.
She apparently didn't realize that in international arrivals she could not go to meet him in the secure area.
Levy said Cisowski, in looking for her son, was directed by airport staff to a customs inquiry office on the arrivals level around 7 p.m.
He said officials there advised her he had not yet arrived at the secondary customs screening point.
"For some reason, and we don't know why ... he didn't go to the exit point out of customs,'' said Levy.
Levy said Cisowski couldn't have paged her son in the customs hall from the public area because of a Canada Border Services Agency policy against public-address pages for passengers there.
"The customs hall area is an area where, other than emergency pages. . . their policy does not want paging done,'' he said.
"That is something obviously that we want to review with them -- say is there an opportunity to look at different procedures and or another way to do that.''
After hours of waiting, Cisowski left, making the five-hour drive back to Kamloops, only to find a message waiting for her asking her to come back. Once she returned, she learned her son had died.
Security was called after reports a man was throwing furniture and wielding a stapler.
One witness has said when RCMP arrived, they almost immediately shot Dziekanski with a Taser.
An autopsy did not immediately reveal the cause of death.
Levy said the airport continues to look into the incident and completing the review could take a couple of months.
"As we see things, if there's things that come up that we need to change, we'll take immediate action,'' he said.
"We're not going to wait to get to the end of it and then say, do this.''
Levy called the incident a "great tragedy'' and said the airport authority offers its condolences to Dziekanski's family.
Larry Berg, YVR Airport Authority president, said in a statement the uncompleted review so far reveals the safety and security needs of airport passengers are being met.
But he also noted the airport is evaluating security procedures, the provision of translation services, its response to medical emergencies and communication with Canada Border Services in the wake of what he called an "extraordinary and tragic occurrence.''
He refused to reveal more, saying the airport respects the privacy of those involved and believes the best way for the family to receive information about it is through the coroner's office.
The airport authority recognizes there are a lot of questions surrounding the fatal confrontation, he said.
No one from the airport has commented in the almost three weeks since Dziekanski died.
"We think it's appropriate now that we get out there and share at least what we're doing in the way of working with the coroner and what information we have at this point,'' Levy said.
"In terms of safety and security of the public and people that work here and our employees, we're confident that the safety and security procedures we have are appropriate.''
Meanwhile, a man who recorded Dziekanski's fatal confrontation with police on video was in court Friday to get the recording back.
The lawyer representing Victoria resident Paul Pritchard said he's been assured by Department of Justice officials that the RCMP will return the recording next week.
Pritchard turned over the video voluntarily on assurances it would be returned within 48 hours but police later balked, saying it was crucial to their investigation.
Police appeared to back down on Thursday but noted Dziekanski's mother did not want the video of her son's final minutes shown in public.
Pritchard's lawsuit in B.C. Supreme Court was adjourned until next Thursday. Lawyer Paul Pearson said he'll pursue the matter vigorously if the Mounties don't turn over the recording by then.
Pritchard said he will give a copy of the recording to Dziekanski's mother to "let her get the closure she needs.
"After that, like I said, I want it to get out to the media. As far as I know that's still the plan.''
Pritchard said he feels a bit uneasy being thrust into the public eye.
"I mean nobody wants to be the guy that sues the RCMP,'' he said outside the courthouse in Victoria. "But, like I said, I felt that I was compelled to do it. It's my duty as a Canadian citizen.''
At a news conference Thursday, Pritchard said one of the two Mounties who came to deal with Dziekanski asked as he came in whether he should use the Taser.
Pritchard said he saw Dziekanski shocked by the stun gun almost immediately.
The Mounties have asked an independent observer attached to the Commission for Public Complaints Against the RCMP to watch over their internal investigation of the airport Taser incident.
Solicitor General John Les said the RCMP are willing to change the way these types of incidents are being investigated.
"The RCMP have asked the federal police complaints office to monitor the investigation right from the very beginning, anticipating that obviously this is a pretty controversial set of circumstances that occurred there,'' said B.C. Solicitor General John Les.
"They are not brushing off the need for a different model for monitoring complaints. They recognize that these things have to be done on a basis that is beyond reproach.''
The independent observer is part of a pilot project launched within the commission last March.
