A French catering firm employee spent 40 hours cowering alone under his bed, terrified he would be killed, as Islamist militants took over the In Amenas gas facility in Algeria where he works, he said on Friday after being freed.
Still badly shaken, Alexandre Berceaux told Europe 1 radio he had survived by staying in his room away from other foreigners, hidden behind a barricade of wooden planks and having Algerian colleagues sneak him food and water.
Pulled to safety on Thursday evening with other foreigners by Algerian soldiers who stormed the site, Berceaux had been so scared of being discovered that he only opened his bedroom door if the person knocking gave a secret password.
"I was completely isolated ... I was afraid. I could see myself already ending up in a wooden box," Berceaux said in a radio interview from the military base where he and other freed hostages were taken by the Algerian army.
As the news eventually reached him via his Algerian colleagues, who were free to move about the site, that al Qaeda-militants had taken control of the site, Berceaux rationed out his food, having no idea how long he could be stuck, he said.
"Yesterday, when the Algerian solders, to whom I'm grateful, came to get me, I didn't even know it was over. I expected to spend another night there," he said.
"They were with some of my colleagues, otherwise I'd never have opened the door."
More than 20 foreign hostages were still unaccounted for on Friday and their captors threatened to attack other energy installations after the Algerian army assault to break the siege resulted in dozens of deaths.
At least eight foreigners were among thirty hostages killed in the raid, along with at least 18 of the captors.
The attackers said they took over the site in retaliation for France's military campaign against Islamist rebels in neighbouring Mali. Some hostages remained inside.
Berceaux, who works for French catering firm CIS which employs some 150 Algerians at the site, said Wednesday's attack began with a spray of gunfire and a call for everyone to stay where they were.
He said he was confused because he knew the site was protected by security guards.
"I heard a huge amount of shooting. There was an alarm telling us to stay where we were but I didn't know if it was real or a drill," he said.
"Afterwards, as time went on, I learned it was a hostage-taking. It was all word of mouth. Nobody really knew what was going on."
The French government said earlier it was in contact with two freed French hostages but had no information on two other French nationals possibly caught up in the siege.
Another Frenchmen was among those killed in the rescue assault, according to a local source.