PARKLAND: Aria Siccone is haunted by the image: A terrified boy knocking on the door of her locked classroom as a gunman started firing at the Marjory Stoneman Douglas High School two week ago.

She said no one let him in out of fear that the shooter would follow. He was fatally shot. Under heavy police guard, Siccone and hundreds of others returned to the high school Wednesday for the first time since 14 students and three staff members were gunned down. The half-day began with fourth period so the survivors could first see, hug and cry with the same people they were with during the shooting. “The one thing that bothers me the most ... is how I saw the boy in the door and we couldn’t let him in and that just hurts a lot,” said Siccone, who is 15. If they had, “The shooter could have followed him in and hurt so many more people.” The hundreds of police officers on hand for the school’s reopening brought comfort dogs, a donkey, and horses, one of which had “eagle pride” painted on its side. A nearby woman held a sign offering “free kisses.” After school dismissed, members of the Guardian Angels wearing their trademark red berets lined the streets at a crosswalk. “In the beginning, everyone was super serious, but then everyone cheered up and it started being the same vibes we had before the shooting,” said Kyle Kashuv, a junior who said he hugged every single teacher. Kashuv said he was amazed by the outpouring of support from the community, including the police presence, the animals and many well-wishers. There were letters from all over the world and “banners on every single wall,” he said. More than a thousand miles (kilometers) to the north, President Donald Trump convened a gathering of bipartisan lawmakers at the White House on Wednesday, during which he called for fast, substantial changes to the nation’s gun laws. He criticized lawmakers for being too fearful of the National Rifle Association to take action. The corporate world took action as well: Dick’s Sporting Goods announced Wednesday that it would restrict the sale of firearms to those under 21 years old, and would immediately stop selling assault-style rifles. Its CEO took on the NRA by demanding tougher gun laws. Later in the day, Walmart announced that it would no longer sell firearms and ammunition to people younger than 21 and would also remove items resembling assault-style rifles from its website. At Stoneman Douglas on Wednesday, some of the police officers guarding the nearly 3,300-student school carried military-style rifles, and Superintendent Robert Runcie said the police presence would continue for the remainder of the school year. The heavy arms rattled some students. “This is a picture of education in fear in this country.” The National Rifle Association “wants more people just like this, with that exact firearm, to scare more people and sell more guns,” said David Hogg, a 17-year-old senior and shooting survivor at Stoneman Douglas who has become a leading voice in the student movement to restrict assault weapons. Florida lawmakers also continued their investigation of how the suspected shooter, Nikolas Cruz, managed to slip through local law enforcement despite previous warning signs. The Florida House voted Wednesday to subpoena records from Broward County and the school board, as well as sheriff’s offices in Broward and Palm Beach counties and the city of Coral Springs. Among items requested from the school were documents on a mentoring program aimed at alternatives to the juvenile justice system. Critics have suggested the program led to lenience for Cruz, but the superintendent said Wednesday that the suspect was never part of the program. Florida Gov. Rick Scott said he hopes a gun and school-safety bill is passed before the annual legislative session ends March 9. The measures he proposed did not include arming teachers, but he declined to say whether he would veto a sweeping package that includes that provision. The Broward superintendent has spoken out against the idea of arming teachers. At Stoneman Douglas, about 150 grief counselors were on campus “to provide a lot of love, a lot of understanding” and to help students “ease back” into their school routines, Runcie said. The freshman building where the February 14 massacre took place remained cordoned off. Students were told leave their backpacks at home. Principal Ty Thomas tweeted that the school’s focus would be on “emotional readiness and comfort, not curriculum.” In each classroom, colored pencils, coloring books, stress balls and toys were available to help students cope. “It’s not how you go down. It’s how you get back up,” said Casey Sherman, a 17-year-old junior. She said she was not afraid to return, “just nervous.” Many students said the debate over new gun laws helped them process the traumatic event and prepared them to return. Alexis Grogan, a 15-year-old sophomore, was concerned that it might be too soon to go on as usual without slain friends such as Luke Hoyer, who sat two seats behind her in Spanish class. “Seeing everyone was good, but emotionally I was in shambles. I probably broke down into tears 10-plus times and had to walk out of my classes multiple times throughout the day,” she said.