Indonesia Tsunami: "Seventeen" was performing at a marquee at the Tanjung Lesung Beach Resort

The band was revving up the crowd at the private, beachside concert, the lead singer punctuating musical notes with pumping fists - "We. Are. Seventeen!" - unaware of the approaching danger.

As he walked across the stage Saturday night, a tsunami wave hit the shore of Tanjung Lesung beach on the western tip of Java, knocking the stage out from under the band and bringing the concert to a sudden and tragic end.

In a video recorded by someone standing several yards away, the stage - with the band members on it - briefly floats as the water hits and then is washed away. Band members disappear underwater. People in the audience scream as they try to flee the approaching seawater and music equipment. Then the video abruptly ends.

According to Reuters, four people connected to the band were killed: bassist M. Awal "Bani" Purbani, road manager Oki Wijaya, guitarist Herman Sikumbang and crew member Ujang.

The band's drummer was still missing, as well as the lead singer's wife.

One crew member, identified by Channel News Asia only by the first name Zack, said he survived by holding on to part of the collapsed stage.

"Underwater, I could only pray 'Jesus Christ, help!'," Zack said of his struggle in the water. "In the final seconds, I almost ran out of breath."

The private concert by Seventeen was part of an end-of-year celebration for Perusahaan Listrik Negara, the country's electricity utility, according to Channel News Asia. Twenty-nine people who attended were killed by the tsunami waves.

On Sunday, Seventeen's lead singer, Riefan Fajarsyah, posted a tearful video on Instagram, apparently still wearing the shirt in which he had performed the night before.

"Andi, Herman and Ujang have not been found, please pray for them," he said as he wiped away tears. "Please pray also that my wife will be found soon. Please pray also for Bani and Oki (who passed away)."

The washed-away concert was just one of the dramatic stories that emerged after tsunami waves struck Indonesia's Sunda Strait without warning, killing at least 222.

By Sunday night, Indonesian government officials said more than 843 people were injured and 28 were missing.

Indonesian officials postulated that a volcanic eruption caused undersea landslides that generated the massive waves, Stanley Widianto reported for The Washington Post.

Indonesia straddles the Pacific "Ring of Fire," where many of the world's volcanic eruptions and earthquakes occur because of collisions between tectonic plates.

Indonesia authorities had earlier said the wave was not a tsunami but a tidal surge

In December 2004, a tsunami triggered by a 9.3-magnitude undersea earthquake off the coast of Sumatra killed 168,000 in Indonesia.

But Saturday's volcanic event did not create the tremors that typically put coastal residents on tsunami watch - and the government never issued a warning.

That is why Seventeen found itself performing for 200 people Saturday night instead of heading to high ground.

The Jakarta-based rock band formed in 1999 in Yogyakarta. All the members were 17 at the time, inspiring the name, according to an online band history. Their debut album was released four years later, followed by half a dozen more in ensuing years.

Before Saturday's gig, the band had played at the Tangerang City Government Center. They then headed to Tanjung Lesung beach for the electric company gig.

They were two songs into their set when the wave struck.

One moment, Fajarsyah was singing on a brightly lighted stage; the next moment, the tsunami wave had swept him out to sea, he told an Indonesian news station, an interview that was later transcribed by the Telegraph.

It was difficult to see in the dark, Fajarsyah told the TV station, but he could hear cries around him and make out flailing hands as people tried to stay above water.As the noises around him faded, he said, he thought that the concertgoers around him had drowned and that he may be next.

"I didn't think I could make (it) to the beach line," Fajarsyah said. "I feel I am really in the sea and about to die."

He tried fruitlessly to swim against the rushing water, but salvation came in the form of a floating box. He latched on to it and used it to swim to a tree. Half an hour later, with the water receding, he climbed down from the tree, covered in scratches. He had one singular thought:

"I have to find my band family as well as my wife."