"My heart sunk. I was sick to my stomach," said resort president Paul Caldwell after getting a call about 10:30 p.m. from his staff that the 15-year-old buildings full of guests were sinking into the ground.
"No doubt there would've been injuries if they hadn't gotten the building evacuated," he said during a live news conference.
He said after the windows began to shatter, a guest ran into the street to flag down resort personnel.
Firefighters arriving on scene immediately went door-to-door of building 104, a three-story building of garden-style apartments, to help guests escape from the splintering and cracked building frame.
The building was sheared nearly in half.
About 20 individuals - men, women and children - left behind everything they brought to their vacation rental. The American Red Cross is on scene to assist the displaced guests.
The affected building connects by breezeway to a center building that houses an elevator shaft, said Lake County fire chief Tony Cuellar.
He said minutes after firefighters escorted the guest out through that center building, it buckled into the shifting ground.
An adjacent building was also evacuated and 16 people had to leave, Cuellar said.
"It could've taken a lot longer but we acted immediately," he said.
All guests had been accounted for and no one was injured. Caldwell said they were relocated to other buildings on the property.
"There's no other units affected except for a loss of power along east side of property," he said.
Firefighters are awaiting engineers to assess the damage the gaping hole caused.
The cavities form as soft limestone below Florida's surface dissolves and collapses with acidic rainwater that filters through the soil. Construction, groundwater pumping and drought followed by heavy rain can accelerate the erosion process.
The water dissolves limestone, causing sands to migrate through and form a hole on the surface-like the neck of an hourglass.
Sinkholes cost Florida residents millions in structural damage and insurance each year.
Experts in Lake County recently told the Orlando Sentinel the region could expect more collapsing earth as companies that repair sinkholes are seeing an increase in complaints.
Geologists say sinkholes have always been a part of life below the crust in the Sunshine State but it's debatable whether they are increasing.
Sinkholes are notoriously frequent in the Tampa Bay area, where one man suffered a dramatic end.
In March, a 50-foot-deep sinkhole swallowed 37-year-old Jeffrey Bush while he was sleeping inside his home. The home was condemned and Bush was declared dead.
Officials investigated a possible sinkhole at a Winter Park, Fla., home in June after the homeowner's pool cracked and shifted in the ground. The hole - 40 to 50 feet wide and 30 to 40 feet deep - stabilized and was just feet from Lake Killarney.
That hole is only 1 1/2 miles from the infamous 1981 Winter Park sinkhole that swallowed a car dealership and home in its 320-foot-wide and 90-foot-deep opening.
Three years ago, sinkholes collapsed lanes of U.S. Highway 27 in east Polk County. And several years before that, a sinkhole that opened up on Scott Lake swallowed enough water to make the shoreline recede dramatically in a Lakeland-area exclusive neighborhood.