Terrified students at UCLA used whatever they could to barricade themselves inside classrooms as a crazed gunman stalked the campus Wednesday.
But working against them here was a flaw that could have proven tragic: The doors open outward and do not have locks.
Safety expert Bill Stanton showed Inside Edition how to do it.
"I am very proud of [the UCLA students]. They looked for anything and everything to secure those doors," he said.
Stanton said to take something as simple as a screwdriver and wedge in the door handle, then step away. A folding chair could also be used to block a door as well.
Stanton also demonstrated how to build a strong barricade if an unthinkable situation like yesterday's UCLA shooting happens.
He said to take as much material available like chairs, tables, desks, “there is never enough stuff,” to put in front of the door.
The killer, 38-year-old Mainak Sarkar, was a disgruntled Ph.D student who shot Professor William Klug, whom he accused of stealing "intellectual property."
Police say they found a "kill list" at Sarkar's home. On the list were a woman reported to be ex-girlfriend found slain in Minnesota.