Faneuil Hall bar admits it screwed up the night it didn't check the women's room at closing and so missed the woman passed out in a stall there

A woman attending a work event at Ned Devine's in Faneuil Hall Marketplace on Sept. 25 told police the last thing she remembered was going into the women's room after 8:30 p.m. - until she woke up in a stall around 2:15 a.m., all the lights off and nobody else in the locked-up bar.

"This was an unfortunate error," bar attorney Dennis Quilty acknowledged at a Boston Licensing Board hearing this morning.

"This is absolutely frightening to me," board Chairwoman Kathleen Joyce said.

Quilty and bar managers said a local business had taken over the bar for an event that night and that the place had closed early, around 11 p.m. - with the woman, who had arrived at the event around 6:45 p.m., slumped over in a stall in the women's room, a stall nobody on staff had remembered to check.

When the woman came to, around 2:15 a.m. and realized she was all alone in the bar, she called 911 and went to open the front door for police, according to a police account. She told officers she'd had just one drink, an espresso martini, as she conversed with a group of co-workers, until she went to the women's room around 8:30 p.m., as she exchanged phone texts with a friend.

One of the two bar managers on duty that night told the board a review of surveillance video showed the woman had actually had at least two drinks that night - the video showed her getting served by two different bartenders.

But regardless, the manager acknowledged, she or somebody else on staff should have checked the restrooms before shutting down and locking up for the night.  She said she and the other manager that night "weren't on the same page" for some reason. "Normally we check each bathroom and we just missed it."

"Obviously, we're very glad this woman was not hurt in anyway. but it was a mistake we take responsibility for," Quilty said, adding the bar's owner, the Briar Group, has retrained its staff to do "double and triple checking" of every last space in the bar at closing to ensure nobody is left behind.

Police told the  board the woman had a toxicology screen done to check to see if she might have had something slipped into her drink. It came back negative, police said.

The board decides Thursday whether the incident requires any sort of official sanction.