McKenna, 15, was on his way to use a bathroom when he saw Nikolas Cruz loading his weapon.
“You’d better get out of here,” Cruz said, according to McKenna. “Things are gonna start getting messy.”
McKenna froze for a second – then fled.
As he made his way out of the building, he said, he saw assistant football coach Aaron Feis unlocking a gate in preparation for dismissal.
“I told him I saw a gun,” McKenna said. “He said ‘let me go check it out.’ Then he drove me to the baseball field, dropped me off, and went back to the school. That’s the last I saw of him.”