The door to the Kate & Hale clothing store dressing rooms previously opened to the First National Bank of Port Jefferson bank vault.
Giavanna Diesso, 14, of Smithtown, learned that history lesson the hard way Tuesday when she was locked inside.
"It just, like, slammed and clicked so I was, like, just what happened?" she recalled.
What happened was her 7-year-old brother Vincent playfully pushed the door shut while his sister was inside.
"I didn’t think that it was actually going to close," the boy said.
It took Port Jefferson firefighters drilling inside to free her. Rescuers, via 911, were called when store employees couldn't get the door open.
It all happened about 1 p.m. on Tuesday, Suffolk police said.
Firefighters had to use air chisels and hammer drills to "breach" the 12-inch wall, the village fire department said in a Facebook post.
Video posted on its page showed firefighters drilling through the wall. Once firefighters made the hole big enough, the girl was pulled out through it. She was not injured, the police department said. The video shows the girl, in a pink top, being helped out through the wall by firefighters, to applause.
"I think I was too shocked to be really too scared," she said.
Giavanna and Vincent's mother, Danielle Diesso, heard a loud sound, and it turned out the noise heralded her daughter being locked inside.
"I actually heard the door close and slam, and it was a very loud slam as I was paying," the mother said.
Steve Erland, the third assistant fire chief of the Port Jefferson Fire Department, said: "It was a very well built wall; they built walls very well 100 years ago."
The department got help from local contractors and their equipment.
It took about 90 minutes or so before the girl could be freed.
"We train on a lot of different construction techniques and ways to either secure walls, go through walls, break into walls obviously — never a safe, but now we know that, so …" he said.
Danielle Diesso said: "Once she got out, I ran over to her, and she ran over to me, and I just hugged her with so much relief that she was safe and in my hands again, in my arms again."
She added: "I hope that we can laugh about it in a couple of days. I still feel very awful that there’s damage to the wall. I feel awful that it was such an ordeal."
A locksmith came to disable the lock. And there's now a small chalk board urging: "Please Do not touch the door."
With Steve Langford