The fisherman was jolted awake by the powerful earthquake and ran with his screaming neighbours to high ground.
He said they watched as the sea first receded and then came roaring back "like a big wall" that swept away their entire village.
"Suddenly trees, houses and all things in the village were sucked into the sea and nothing was left," Joni Sageru recalled on Thursday, in one of the first survivor accounts of this week's tsunami that slammed into islands off western Indonesia.
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The death toll rose to at least 394 peope as officials found more bodies, although hundreds of people remained missing.
Bodies swept to sea
Harmensyah, head of the West Sumatra provincial disaster management centre, said rescue teams "believe many, many of the bodies were swept to sea."
Along with the 33 people killed by a volcano that erupted on Tuesday more than 1,300 kilometres to the east in central Java, the number of dead from the twin disasters has now topped 400.
Mount Merapi began rumbling again on Thursday, after a lull that allowed mourners to hold a mass burial for its victims.
There were no reports of new injuries or damage.
The catastrophes struck within 24 hours in different parts of the seismically active country, severely testing Indonesia's emergency response network.
Aid workers trickling into the remote region found giant chunks of coral and rocks in places where homes once stood. Huge swaths of land were submerged and swollen corpses dotted roads and beaches.
Toddler found alive
In a rare bright spot, an 18-month-old baby was found alive on Wednesday in a clump of trees on Pagai Selatan - the same island where the 30-year-old Sageru lived.
More than 100 survivors crowded a makeshift medical centre in the main town of Sikakap on Pagai Utara - one of the four main islands in the Mentawai chain, located between Sumatra and the Indian Ocean.
One of the hardest hit areas with 65 dead was the village of Pro Rogat, on Pagai Seatandug island.
Villagers there huddled under tarps in the rain and told how many people who had fled to the hills were now too afraid to return home.
Officials say a multimillion-dollar tsunami warning system that uses buoys to detect sudden changes in water levels broke down a month ago because it was not being properly maintained.
The system was installed after a monster 2004 quake and tsunami that killed 230,000 people in a dozen countries.
A German official at the project disputed there was a breakdown, saying Monday's 7.7-magnitude quake's epicentre was too close to the Mentawai islands for residents to get the warning before the killer wave hit.
"The early warning system worked very well - it can be verified," said Joern Lauterjung, head of the German-Indonesia Tsunami Early Warning Project for the Potsdam-based GeoForschungs Zentrum.
He added that only one sensor of 300 had not been working and said that had no effect on the system's operation.
At the Mount Merapi volcano, hot clouds of ash spewed from the mountain on Thursday afternoon, according to the Indonesian volcanology agency Subandriyo, but it was unclear whether the new activity was a sign of another major blast to come.
Residents from Kinahrejo, Ngrangkah, and Kaliadem - villages that were devastated in Tuesday's blast - crammed into refugee camps.
Thousands attended a mass burial for 26 of the victims, 10 kilometres from the base of the volcano.
