There were about two dozen people on the observation deck inside the 126-year-old Washington Monument when the earthquake struck five weeks ago.
It was August 23 at 1:51 in the afternoon when a security camera attached to the ceiling of the observation deck caught National Park Service ranger Niki Williams' reaction to the shaking. Williams can be seen looking up after the shaking ensues, but there's no panic.
She appears to speak calmly with tourists. Then, as the shaking becomes more violent, she looks up again and immediately starts ushering people down the stairs, just as they are pelted by falling debris.
One or two people appear to fall down briefly, then get back on their feet and join others as they crowd down the stairs. Some are carrying or holding onto children. A short time later, Williams is seen running through the observation deck, making sure everyone is out.
Williams, "Early Show" co-anchor Erica Hill noted, is being called a hero by the National Park Service. But Williams told Hill that, when the monument began to shake, she was "very, very frightened."
"I initially just wanted to run down the stairs by myself and away from everything," she said.
However, she didn't run away. She snapped into action, helping those who needed assistance down the monument's steps.
"I realized I had to take care of these 20 people. I was responsible for them," Williams said. "So I go down to that next level, you see me going down the stairwell to open up the emergency exit and get them down the stairwell."
Williams said she thought "we were under some sort of attack."
"I did not have any indication of what had happened until about two minutes after," Williams said. "I was walking down the stairwell to assist a visitor and a park police officer came across my radio and notified me that it was an earthquake that had happened, which calmed me a little bit. But then I realized there could be aftershocks while I was in the stairwell."
Visitors, too, who heard Williams' radio, calmed down a bit when they heard it wasn't an attack, Williams said.
She recalled, "There was one visitor who had trouble going down the stairs, so I was assisting her and she was elderly. And so, for her to hear that, I could see her visibly relax right in front of me."
Williams even went back up to the observation deck to make sure no visitors were left behind.
Watching herself on the surveillance video, Williams said is "absolutely strange."
She said, "When I had gotten down to the bottom afterwards, I was running through the things I could have done differently and I thought I hadn't reacted quickly enough. But then when I saw the video, I realized there was very little time between what was going on and getting down that stairwell."
No one was injured in the monument during the earthquake, but the people at the top, noted CBS News correspondent Chip Reid, had to walk the 897 steps to the ground level.
The monument, closed indefinitely, is going to be inspected today. Four engineers are going rappel down the monument to see exactly how badly the monument was damaged. The job will take five days.
So would Williams return to the monument?
She told "Early Show" co-anchor Erica Hill, "I hope that they can guarantee me that it is secure before I go back inside."