Mooney didn't immediately know the woman's condition, but he said she was conscious when she was transported to the hospital for treatment.
The woman was trying to catch an elevator from the casino hotel's mezzanine level, Mooney said.
She didn't make it in time - and the momentum pushed the wheelchair through the now-closed doors on the second floor. The elevator car was already on its way up when she fell. Her wheelchair fell on top of her.
When firefighters arrived, they found the elevator doors off their tracks.
Two Bally's workers who rushed over to help were injured while looking down the elevator shaft. Mooney wasn't sure how.
Firefighters had to rig a rope and pulley system to get the injured woman out, Mooney said.
A nursing supervisor at AtlantiCare's Atlantic City campus wasn't immediately authorized to release the injured woman's condition.
Bally's spokeswoman Alyce Parker said the injured woman was staying at the hotel. She said the company is aiding the investigation.