And they didn't want to talk about it.
The night before, after the McClymonds High School boys basketball team beat Sacramento's Grant High School at home, someone fired into the crowd as they left the game.
The gunfire injured three bystanders, all high school students.
To some, including Kwok, the shooting felt like a violation of a sacred space, an unwelcome reminder of the dangers its students face even while engaged in the most wholesome, tradition-bound high school rituals.
"If anything, it made us aware of the difficulties students at this school have," said Kwok, 22, who teaches mostly ninth- and 10th-graders at EXCEL High School, a small school that opened in 2005 on the McClymonds campus.
To others, the nonfatal incident was a deep disappointment, not to mention an invitation for negative press. But it wasn't something to dwell on or, in some cases, even talk about.
After all, no one got killed.
"In this neighborhood, the kids just bounce back from things like this," said John Hodges, a McClymonds security officer who said his unofficial job description includes father figure, grandfather figure, counselor and even teacher.
"That's kind of frightening for me, in a sense the quick tendency to forget."
Kwok gave each of his classes the opportunity to discuss the shooting. All but one group declined, saying they'd rather stick to the biology lesson. So they did.
That day, Kwok discovered what some of his students had known for years: Simply carrying on with life can be a great relief.
"I think it was actually a distraction and a way to get away from what happened," Kwok said. "I kept thinking about it. I didn't really know how to feel or respond."
Kwok grew up in a comfortably middle-class family in St. Louis. He went to high school without the weight of his own mortality or that of his friends on his shoulders. Then he began teaching in West Oakland, a predominately low-income, African-American community whose rich history and sense of community is often overshadowed by gun violence.
Kwok knew that many of his students had led difficult lives. He knew some were born into generations of poverty. But he never thought a 14-year-old boy would miss his class because of a bullet wound.
"It's hard to imagine it's an accomplishment for students just to make it to school some days," Kwok said.
Robert Brigham, one of Kwok's biology students, is the teammate of one of the shooting victims. The 16-year-old junior varsity basketball player said he wasn't angry, exactly, about the outbreak of senseless violence.
"I was more disappointed in the people around us," Brigham said, stressing that the shooting had nothing to do with the school itself. "We were trying to show the other team a good time."
Some of Brigham's classmates didn't want to be interviewed about the shooting. Two of them complained that people were making too much of it especially the school district, which instituted a new set of safety measures, including a no-backpack rule, at all district sporting events.
But Brigham said he doubted his peers actually saw the incident as a minor event. If it seemed that they took the shooting lightly, he said, it might be because worrying won't change what happened.
"You try not to think about bad things, because when you think about bad things, then bad things happen to you," Brigham said.
Brandon Stewart, another one of Kwok's students, said sometimes his gaze drifts out the window, and he wonders about what's going on "outside," beyond the typically safe walls of his high school.
It's easy to lose focus when he thinks about those things, he said. So, more often than not, he doesn't.
"Stuff happens, you know, and you just have to go on with life," said Stewart, 15.
Last April, 17-year-old Derial Morris Jr., a McClymonds student, was shot and killed in a friend's apartment building.
Last week, the fatal shooting of 16-year-old Tanika Wade was the talk on campus. She attended McClymonds last year, as did her boyfriend, who had reportedly been playing with a pistol when he shot her in the head.
But that happened on Monday, Hodges said. By the end of the week, he predicted, the students would be on to something else.
Read Katy Murphy's Oakland schools blog at http://www.ibabuzz.com/education.