Kody Baumler, 16, said he felt upset as he walked back into school Wednesday.
"Sam was one of my friends," Baumler said, expressing surprise that Hengel would do such a thing.
Kordel Brezsko said he was "kind of a little depressed today" but that he felt safe. "I don't think it will happen again."
The high school serves about 700 students in the city of 12,000 that sits on the border with Michigan's Upper Peninsula. District officials had closed the building Tuesday as investigators combed through the classroom and interviewed students at their homes. Classes were set to resume Wednesday.
"I don't know what's going to happen," said 15-year-old Austin Biehl, a wide receiver and point guard on the school's junior varsity football and basketball teams who was in the class that Hengel held hostage. "It's going to be strange."
Officials said grief counselors and others would be available for students who want to talk.
"We understand there is a fear factor that we must overcome," said Principal Corry Lambie. "But we're the adults, the leaders in the building, so we need to take care of that for our kids."
The principal said the district will evaluate whether that means installing metal detectors at the school in the future. Authorities and students say after being excused to use the bathroom, Hengel had returned to teacher Valerie Burd's West Civilization class on Monday afternoon with a backpack containing two semiautomatic handguns, ammunition and a knife. He had more bullets in his pockets.
Still, Marinette County District Attorney Allan Brey questioned Tuesday whether tighter security was worth the cost, noting the school and police had emergency plans in place and that the plans would be reviewed and updated after what happened this week.
"They knew what to do if something terrible happened," Brey said Tuesday. "We live in a democracy where we balance freedoms and our personal protection. I'm sure that we could have airport security at the Marinette High School if somebody wanted to step up to the plate at five to ten million bucks a year.
"I don't know that our school district wants to do that. As a taxpayer in the school district I'm not sure I want to pay for that."
While in the classroom, Hengel fired at the wall and a movie projector, but students say he never made any demands and didn't seem intent on hurting anyone. His classmates spent hours chatting and laughing with him about everything from deer hunting to movies, trying to keep him calm. Hurd acted as his go-between with police through a landline phone in the classroom.
As the standoff dragged into the evening, students started telling Hengel they had to use the bathroom. He let three go, as well as another who looked sweaty and pale and a girl who was in tears. But that was it.
Another student who had to urinate was forced to use a garbage can, stinking up the classroom, Biehl said. Burd put down the phone to give the student a spray bottle. Hengel then fired off three rounds, hitting the room's telephone twice and a computer.
SWAT officers, fearing the worst, broke down the door and rushed at Hengel. He dropped his gun, picked up the one on the podium and pointed it at his head, Biehl said. An officer grabbed his arm just as he squeezed the trigger, but it was too late to save him.
Hengel's family said in a Tuesday evening statement that they'd seen "no indicators" from the teen who loved "anything that included his family and the outdoors" to make them think something was wrong.
"We wish we knew and could provide insight to what led Sam to take these drastic acts," the statement said. "In the coming days and weeks as we talk to other people involved in this incident we hope reasons surface so we too, can stop asking ourselves `why?"'