Estancia High School Principal Kirk Bauermeister was in his office a few minutes before 1 p.m. Friday, when a student ran by his office yelling there was a gunman.
Bauermeister sprinted in the opposite direction of the fleeing student toward the attendance office. He saw staff hiding or pulling students toward cover.
"I had no idea what was going on," he said.
A few minutes earlier, Michael McHugh, a 35-year-old Costa Mesa man, had tried to remove his daughter from class, police would later assert.
A staffer realized the student's family had an active restraining order against McHugh and asked Assistant Principal Mike Sciacca to intervene, according to school officials.
Sciacca, a new administrator at Estancia, told the father he wasn't authorized to pick up his daughter and asked him to leave campus.
"At that point, things happened very quickly," Sciacca said.
McHugh was carrying a white trash bag filled with bottles, cans and other garbage, Sciacca said.
He reached inside and pressed the muzzle of a replica handgun against the plastic, showing the bulge of its outline, according to the assistant principal.
McHugh announced that he was taking his daughter no matter what and would kill anyone who tried to stop him, Sciacca said.
It wasn't until police recovered the gun later that Sciacca found out it was a BB gun designed to look like a real weapon.
From about conversation distance, the assistant principal stepped quickly forward and to the side, he said, grabbing McHugh's wrist and trying to wrestle away the gun.
"In all honesty it was self preservation at the moment," Sciacca said.
One of Estancia's three security guards, Xavier Castellano, saw the scuffle begin and took off through the hallways.
Students described him sprinting from room to room, yelling, "It's a gun. It's a gun," warning them to evacuate or dive behind desks.
Meanwhile, Sciacca and McHugh tumbled out of the attendance office into the school hallway moments before Bauermeister ran into the room.
Staff yelled that Sciacca had pushed a gunman through the swinging door, away from staff and students.
"I had no idea what was happening on the other side of that door," Bauermeister said Monday.
He decided to burst through it as violently as he could.
On the other side, he saw Sciacca on top of the man. The 34-year-old assistant principal had pinned McHugh to the ground with the weapon underneath them, Bauermeister said.