"Rabbi, I have a question," he says to his principal, Rabbi Heshy Glass, who is standing with him. "Doesn't it say you can't die while you're learning Torah?"
Glass tells him the story of the Mishnaic sage Rabbi Akiva, who was taken by the Romans while he studied. Like these boys, he tells Begin, he was a Jewish hero, remembered for the ages.
Glass doesn't try to make sense of the tragedy, just to continue the conversation about what is so troubling to Begin and other boys at YULA, many of whom plan to study in Israeli yeshivas when they graduate.
"You hear about tragedies in Israel, but it hits so close to home because this is us next year. Next year we're going to yeshiva," said Chaim Gamzo, a 17-year-old senior. "These guys had their whole lives ahead of them -- like me. I hope to go to yeshiva, to go to college, to have a normal successful life, but they didn't have the opportunity to do that."
At YULA and at Jewish schools around the city, students gathered in special assemblies and prayer services last week.
At Milken Community High School, a special pre-Shabbat healing service on Friday was dedicated to the boys, and students recited Kaddish for them.
"Our students felt deeply connected to these students halfway across the world who were studying Torah and living Torah the same way they are," said Rabbi Shawn Fields-Meyer, rabbi-in-residence at Milken, who led the service.
At Orthodox day schools, students as young as first grade recited psalms and discussed the events, and most middle school classes attended special prayer services. High school students led many of the prayers at a citywide gathering at Young Israel of Century City on Sunday.
At YULA high school, most of the boys wear the same knitted yarmulkes, symbolizing religious Zionism, as the boys who were killed. Most of them spend part of their day studying in a beit midrash but will go on to secular professions. The YULA boys, and other Modern Orthodox high school students, are the American parallels of the boys who were killed.
"I see those pictures of those boys crying, and I know it could be my friends crying," said Begin, who also plans to study in a religious Zionist yeshiva next year.
The bulletin board went up Thursday night in YULA, and by Friday, hundreds of signatures, both in Hebrew and English, adorned a poster of solidarity. That day, the boys held a special assembly where they prayed for the students and their families. Rabbi Marvin Heir, dean of the Simon Wiesenthal Center, parent organization of YULA, talked to them both about the emotional and political ramifications of terrorism.
In a confluence of events, YULA and many other schools had been scheduled for months to hold assemblies hosting the parents of Roi Klein and Noam Apter, two young Israelis who died defending the country. The families were here to be honored at "An Evening of Jewish Heroism" at the Writers Guild theater in Beverly Hills on Tuesday night. The event was sponsored by Bnei Akiva, the religious Zionist youth movement whose ideological founder is the same Rav Avraham Yitzchak Kook who founded Mercaz Harav Yeshiva.
Klein, a major during the Lebanon War in 2006, died reciting the Shema Yisrael prayer as he lept onto a grenade to save fellow soldiers in the battle of Beit Jbeil. Apter, who at 22 had completed his army service, was in his Yeshiva's kitchen in Otniel when heavily armed terrorists infiltrated. Apter quickly locked the door between the kitchen and the dining room, giving other students a chance to flee but sealing his own fate.
The Apter family lives near one of the boys killed in Mercaz Harav last Thursday.
Students were emotional during the assemblies, and lingered to talk to the parents afterward, according to Shalom Ashkenazi, Bnei Akiva's Los Angeles emissary from Israel.
"We must learn from these two boys what is the meaning of life, what it means to be Jewish and to be thinking about Am Yisrael," said Shalom Ashkenazi. "The terrorist chose this yeshiva because it is a symbol of Judaism and a symbol of religious Zionism. When Noam and Roi died, they said to the people of Israel, 'We don't live for ourselves. We live and die for our friends, for the land of Israel, for the people of Israel, and for the Torah of Israel.'"