Terrifying video captured the moment a cop in Australia opened fire Thursday on a knife-wielding lunatic – but also wounded three innocent women caught at the wrong place at the wrong time.

Jerry Sourian, 23, was waving a knife – as he shouted “Allahu akhbar!” or “God is great!” – at a Sydney shopping center, 9news.com.au reported.

A cop yelled at Sourian to get on the ground, but she opened fire twice when he continued charging. An elderly woman began screaming after she was struck, either by a bullet or by shrapnel.

The stricken Sourian, meanwhile, staggers and lunges at other cops converging on the chaotic scene.

He is shot a third time, crumpling to the ground as sirens wail and the wounded woman continues yelling, “I’ve been shot! I’ve been shot!”

The cop who hit the woman told her: “I’m sorry! I’m sorry!”

She and two other women – 60, 65 and 82 years old – were hospitalized in stable condition.

Sourian — who sustained gunshot wounds to his arm, abdomen and thigh – had been reported missing from a nearby psychiatric facility on Wednesday after disappearing two weeks earlier.

Witnesses said Sourian had been “babbling incoherently” and walking around barefoot before the shooting.

A police official said an investigation was launched to determine whether the cops should have used a Taser or pepper spray to subdue the man rather than opening fire in the crowded square.

“A decision was made by those officers in a life-and-death situation,” Assistant Commissioner Denis Clifford told reporters.