There was terror in Terrance Lockett’s voice. The 52-year-old correctional officer had only been on the job for about eight months, and a chaotic and bloody scene was unfolding before him.

The only officer on the unit, Lockett watched as members of the Irish Mob and Universal Aryan Brotherhood prison gangs warred before him.

Lockett quickly yelled out on the radio for help, but incorrectly identified the unit he was stationed in. Interviews with other prison employees show Lockett was at first paralyzed, and only after responding officers and nurses arrived did he finally marshal a panicked inmate back into his cell.

But even that didn’t go smoothly. Prison records show Lockett put one inmate in his cell, but rather than safely lock him in, Lockett pepper-sprayed the compliant man.

Responding correctional officers faced a dangerous situation — many of the prisoners still held weapons, and other prisoners were unable to lock themselves down thanks to a policy at the facility that prevented the dozens of prisoners surrounding the scene from re-entering their cells.

Before it was over four gang members — two from each gang — were dead and four other inmates were injured. It was the deadliest prison riot in Oklahoma history.

WARNING: The following video shows GRAPHIC IMAGES and may be disturbing to some viewers.