A former Parkland, Florida, teacher recounted Wednesday on the stand a student in her Holocaust studies class correctly answering a question seconds before then-teen Nikolas Cruz gunned him down in a school shooting that left 17 people dead.

Cruz, 23, is on trial at the Broward County Courthouse in Fort Lauderdale for the Feb. 14, 2018, massacre at Marjory Stoneman Douglas High School. 

In October, he pleaded guilty to 17 counts of first-degree murder.

The penalty trial, which began Monday, will determine whether he is sentenced to death or life in prison without parole. 

PARKLAND SCHOOL SHOOTING TRIAL: JURORS WATCH GRAPHIC VIDEO OF SLAUGHTER

teacher Ivy Schamis testifies about Nikolas Cruz's rampage

Former Marjory Stoneman Douglas High School teacher Ivy Schamis describes the carnage in her classroom during the Parkland mass shooting that killed 17 at the penalty trial of gunman Nikolas Cruz. (Mike Stocker/South Florida Sun Sentinel via AP)

Ivy Schamis became tearful as she recalled lecturing about the 1936 Olympics in Nazi Germany when star swimmer Nick Dworet said that Adolf Dassler founded the Adidas shoe company and Dassler's brother launched the rival Puma brand. 

PARKLAND SCHOOL SHOOTING TRIAL: ‘THINGS ARE ABOUT TO GET BAD,' GUNMAN WARNS STUDENT

 "It was really seconds later that the barrel of the AR-15 just ambushed our classroom," Schamis testified, dabbing her eyes with a tissue.

Parkland mass shooter Nikolas Cruz sits at defense table during jury selection

Marjory Stoneman Douglas High School shooter Nikolas Cruz is shown at the defense table during jury selection in the penalty phase of his trial at the Broward County Courthouse in Fort Lauderdale, Florida, June 28, 2022.  (Amy Beth Bennett/South Florida Sun-Sentinel via AP, Pool)

"It came right through that glass panel and was just shooting everywhere. It was very loud. Very frightening. I kept thinking about these kids who should not be experiencing this at all."

PARKLAND SHOOTER NIKOLAS CRUZ: FLORIDA TRIAL BEGINS OVER WHETHER GUNMAN WILL FACE DEATH PENALTY

Cruz, who was expelled from the school the prior year, had shoved his rifle through a glass window on the internal door to spray the first-floor classroom with bullets.

Two of Schamis' students were killed: Dworet and Helena Ramsay, both 17. Three others were wounded.

Ivy Schamis dabs her eyes with a tissue as she testifies about the murder of her two students

Teacher weeps on the stand July 20, 2022, at the sentencing trial of gunman Nikolas Cruz, as she recalls the murder of two of her students at Marjory Stoneman Douglas High School during the Parkland mass shooting that killed 17. (Mike Stocker/South Florida Sun Sentinel via AP)

The prosecutor showed Schamis photos of the slain students, and she began to sob. "That's my girl, Helena Ramsay," she said. "Nicholas Dworet, handsome boy."

Other teachers also testified Wednesday about the horrifying carnage wrought by Cruz, as he stalked through the halls of the three-story building shooting randomly at human targets.

An athletic director, a coach, a teacher and 14 students died during the rampage. 

CLICK HERE TO GET THE FOX NEWS APP 

Jurors on Tuesday were shown gruesome surveillance footage of Cruz shooting victims at point-blank range, and returning to classrooms to execute some of the injured who lay on the floor.

The trial resumes Thursday morning.

The Associated Press contributed to this report.