Enrique Fritz, who runs the prison in devastated Concepcion, took a major risk last weekend as the tsunami rolled towards town - he decided to free his 103 detainees to avoid loss of life.
"It was a humanitarian decision," he told AFP. "We're very close to the sea, I couldn't leave them locked up to die."
The jail, located just off the town's leafy main square, took a battering from the powerful 8.8 quake that hit Chile on Saturday. The epicenter was not far away.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The roof of the wardens' dining-room crashed to the ground, as did much of the ceiling of the supply room, crumbling around a giant meat slicer that survived the quake.
"It breaks my heart to see the damage," said Fritz, a ranking member of the Chilean gendarmerie that is in charge of prison matters, and who has headed the jailhouse for over 30 years.
"We were the last to leave town," said Fritz, who escaped on foot to the hills after taking a tough decision that could have hurt his career and that went against everything he works for - "letting loose a bunch of criminals and sowing panic among the public was not what I wanted to do."
"But the quake had struck and had rattled them, they were literally climbing the walls," he said.
Fritz said he immediately feared a tsunami and 15 minutes later heard a warning on town loudspeakers urging people to flee.
"So we unlocked the cells and let them out."
Some of the detainees were hardened criminals, he said, but of the 103 prisoners, 70 had already been recaptured with the help of police, some in their homes.
Half of the 70 turned themselves in voluntarily "because they knew we'd find them anyway and that it would them no good."
Because of the damage, the detainees have been transferred inland.
Nine who were hauled in on Thursday were in the local jail, watched over by the 30-odd guards working at the prison.
And had Fritz been in trouble with his superiors? "I haven't heard anything," he said.

