"I had a goal: sacrifice to the homeland," he says, through a translator. "We are in a war; I can only do this (type of) operation."
As CBS News Correspondent Richard Roth reports, he believed he'd be going to paradise, until Israeli soldiers stopped him at a checkpoint.
A lot of what Israel has learned about suicide bombings has come from attacks that didn't happen. More than 300 of them were thwarted just last year, according to the army, and it's not paradise where failed bombers end up - it's prison.
Northern Israel's maximum security Gilboa prison is also where Sayed Ali will be spending the next 10 years.
He was wearing an explosive vest when he was caught. He'd gone to a well-known militant in his village and told him he wanted to die for Palestine.
It was as simple as that.
They weren't recruited. The young men here say they volunteered.
Another volunteer was the 27-year-old Palestinian woman whose bomb blew up a restaurant in Haifa in October 2003, killing 21 Israelis. The man who sent that bomber on her deadly mission was Sammi Jaradat.
"What we are doing is what every human being is waiting for - his turn to die," says Jaradat through a translator. "Instead of waiting for death to come to me, I will go to death."
Like the world outside these cells, prisoners here learned of the London bombings on TV and radio. And to al Ashkar, they were a surprise.
"I was surprised because we explode ourselves in the middle of an occupation," he says. "In London there is no occupation, no need for anyone to explode himself."
But the idea that suicide bombers would seek new targets off the battlefield and on the home front in Western Europe makes perfect sense to Jaradat, who's more experienced in this chilling business and more devout.
"England started invading the Islamic world following the U.S.," he says. "They have to expect that while occupying Islamic lands, the occupied will come to punish them."
Jaradat's punishment is a life sentence here, 21 times over: One for every Israeli his bomber killed.