A normal morning commute turned into every straphanger’s worst nightmare for a Brooklyn woman who was suddenly, violently attacked by a madman in a subway station as two transit workers looked on.

Before Lisseth Choez, 22, knew what was happening, the hulking 6-foot stranger smashed his fist into her cheek. He grabbed the stunned woman’s head, slamming it into an iron gate in the nearly empty waiting area of the Lorimer Street elevated station in Brooklyn.

As two MTA employees watched the assault and screamed from inside their secure booth, the man in the white undershirt kept beating Choez — kicking her and punching her in the head until her eye socket fractured.

She begged the station agents to call police.

He then grabbed her by the neck in a chokehold, lifting the terrified Choez into the air before throwing her like a rag doll to the platform.

It was 10 minutes of hell before police finally showed up and subdued Timothy Prude, 43, who managed to slug a cop during his arrest.

The Aug. 18, 2009, attack never should have happened, Choez claims, because Prude had been in police custody at nearby Woodhull Hospital minutes before, according to a lawsuit she filed last week in Brooklyn Supreme Court.

“She’s still very fragile,” lawyer Alexis Soterakis said of Choez.

The $1 million lawsuit says the NYPD and the city Health and Hospitals Corp., which oversees Woodhull, should have known Prude was dangerous. It was unclear exactly how Prude managed to leave the hospital; Choez accuses both agencies of failing to keep her attacker from “removing himself from custody.”

Choez, who is also suing the MTA, says the transit workers failed to alert police quickly, even as they watched Prude beat her to a bloody pulp.

Station agents aren’t allowed to leave the booth or let anyone inside, said an NYC Transit spokesman, who added that station agents can contact emergency personnel via a booth communication system.

But spokesman Charles Seaton declined to say exactly when or how the station agents who witnessed Choez’s horrifying ordeal contacted police, referring questions about the attack to the NYPD.

But police could not confirm it had Prude in custody prior to the vicious attack on Choez at the elevated station just blocks from her Williamsburg home.

Prude was slapped with second- and third-degree assault charges, menacing and harassment in the incident, and earned additional assault, criminal-mischief and resisting-arrest charges the next day, when he allegedly kicked out the rear window of a police car and tried to climb out, all while handcuffed, according to the Brooklyn District Attorney’s Office.

City sources said that since the arrest last summer, Prude has been transferred several times from jail to Bellevue Hospital and was moved to a state hospital in March.

kathianne.boniello@nypost.com

