HUALIEN CITY, TAIWAN - Most survivors of Tuesday night’s strong earthquake in Taiwan escaped because they were on high floors that did not collapse, allowing rescue workers to find them.

As of Friday morning, 830 people had left the four collapsed or damaged buildings in the Pacific coast city of Hualien. Many broke windows or climbed out via balconies to escape the two worst-hit buildings, a 10-story hotel and a 12-story commercial-residential complex. Firefighters waited below with ladders.

The quake killed 10 people, including hotel guests and workers who were on lower levels of the buildings when the quake struck at 11:50 p.m. Taiwan’s Central Weather Bureau recorded the quake as a magnitude 6 at its epicenter off the coast, and in Hualien it was felt with an intensity of 7, enough to cause widespread damage.

WATCH: Rescuers Work to Find Survivors After Taiwan Earthquake

Angle too steep to climb?

“A sound, it made a sound like a tract of wooden floor boards were ripping apart, for one minute,” said Chang Te-chuan, 77, who escaped the commercial-residential complex’s fourth floor. The building was sliding downward at a steep angle, pushing two lower floors into the ground.

“In my room, all my furniture had been moved into one place, all of it, it was in one place then moved to another, the whole room was tilted at about 45 degrees, and at an angle of 45 degrees I almost couldn’t move from one place to another,” Chang said. “You’d crawl and find yourself sliding. The angle was just too big.”

But with the fourth floor suddenly near the street outside as the whole building tilted, Chang grabbed a flashlight and was able with a firefighter’s help to get out through a window. He and about 100 others spent the next day at an elementary school converted to an emergency shelter.

Rescuers carry a victim recovered from a collapsed Rescuers carry a victim recovered from a collapsed building following a strong earthquake in Hualien County, eastern Taiwan, Feb. 8, 2018. A magnitude 6.4 earthquake struck late Tuesday night caused several buildings to cave in and tilt dangerously. Rescuers carry a victim recovered from a collapsed building following a strong earthquake in Hualien County, eastern Taiwan, Feb. 8, 2018. A magnitude 6.4 earthquake struck late Tuesday night caused several buildings to cave in and tilt dangerously.

?Rescue work focused on lower floors

Within the first 18 hours, the 1,644 firefighting personnel and 1,147 army troops had accounted for 68 people including everyone in the third through 12th floors of Chang’s building, Hualien County Fire Department spokesman Chu Che-ming said.

Seven people were found dead on the two lower floors.

“As for now, from the third through 12th floor, we’ve not found any more signs of additional people being trapped,” Chu said Wednesday night from his rain-soaked tent outside the structure, the Yun Men Tsui Ti Building. “Because the underground floors were rather badly crushed, we’re continuing to look for people there.”

The first and second floors of the building had sunk into the soft ground. Rescue workers said the walls on those floors had been destroyed, leaving just cramped passages between the remaining beams.

As of Thursday evening, rescue workers were still searching for a mainland Chinese family of five, a Canadian couple and a Filipino worker, all believed trapped in the Yun Mei Tsui Ti Building’s second-story guesthouse.

Rescuers are seen entering a building that collaps Rescuers are seen entering a building that collapsed onto its side from an early morning 6.4 magnitude earthquake in Hualien County, eastern Taiwan, Wednesday, Feb. 7 2018. Rescue workers are searching for any survivors trapped inside the building. Rescuers are seen entering a building that collapsed onto its side from an early morning 6.4 magnitude earthquake in Hualien County, eastern Taiwan, Wednesday, Feb. 7 2018. Rescue workers are searching for any survivors trapped inside the building.

?“When a structure is tilting, it’s hard to know where people are,” said Fan Kang-wei, a Red Cross rescue volunteer who helped find victims in Hualien. “They might be crushed by walls or by furniture.”

Firefighters had saved 98 people from the Marshall Hotel, a central Hualien landmark that partly collapsed. One person, a 37-year-old hotel staff person, died there.

Work paused twice Wednesday at the commercial-residential complex. First, firefighters called in steel beams to prop up the structure and stop it from tilting further toward the ground. Later they paused to place cement blocks around the beams to keep them in place.

Damage was less severe at the two other damaged properties, a hospital and a smaller apartment complex.

Sixth floor became the second

Sixty-six year old Chen Chien-hsiang was awakened by the quake, describing the sound as like the explosion of an “atomic bomb.” The man, who lived alone among 80 households in the Yun Men Tsui Ti Building, was pushed into a crevice of his slanted room to fumble through furniture to reach a glass door to a rear balcony. The structure’s tilting made it impossible to stand up, while a power outage created total darkness, he said.

“This was too terrifying. Because it was so dark I couldn’t tell whether I was still in the room,” said Chen, a retired antique dealer. “The whole room was a total mess.”

“Getting out, there was no way to get out. I later used all my strength to crawl, crawled to the rear balcony, little by little moving things in the way to get out and using a lot of strength,” he said. “Outside I saw rescue workers. The sixth floor had turned into the second floor.”

Hualien City, Taiwan Hualien City, Taiwan Hualien City, Taiwan

Elsewhere in Hualien, a tourism and fishing town with a population of about 100,000, people spent Tuesday night outdoors or in their cars. They were afraid that the more than 160 aftershocks, some exceeding a magnitude of 5, would cause more damage. Some stayed in one of the city’s three emergency evacuation centers.

Local government construction officials plan to investigate why a few buildings were damaged while most construction in Hualien, which is used to earthquakes, withstood the shaking.

After a February 2016 earthquake killed 116 people in a toppled apartment complex, investigators discovered liquefied soil and nonstandard construction.