(PHOENIX) -- Jodi Arias stepped down from the witness stand Wednesday after mounting an emotional effort to save herself from death row, insisting to the Arizona jury that an explosive fight with ex-boyfriend Travis Alexander led to his death, and that her lies about killing him masked deep regret and plans to commit suicide.
Arias, 32, will now face what is expected to be a withering cross-examination beginning Thursday from prosecutor Juan Martinez, who has been aggressive to many witnesses throughout the trial and who is expected to go after Arias' claim that she was forced to kill Alexander or be killed herself.
She has been charged with her ex-boyfriend's murder and could face the death penalty if convicted.
Wednesday's dramatic testimony started with Arias describing the beginning of the fight on June 4, 2008 when she and Alexander were taking nude photos in his shower and, she claims, she accidentally dropped his new camera, causing Alexander to lose his temper. Enraged, he picked her up and body-slammed her onto the tile floor, screaming at her, she told the jury.
Arias said she ran to his closet to get away from him, but could hear Alexander's footsteps coming after her down the hall. She grabbed a gun from his shelf and tried to keep running, but Alexander came after her, she said.
"I pointed it at him with both of my hands. I thought that would stop him, but he just kept running. He got like a linebacker. He got low and grabbed my waist, and as he was lunging at me the gun went off. I didn't mean to shoot. I didn't even think I was holding the trigger," she said.
"But he lunged at me and we fell really hard toward the tile wall, so at this point I didn't even know if he had been shot. I didn't see anything different. We were struggling, wrestling, he's a wrestler."
"So he's grabbing at my clothes and I got up, and he's screaming angry, and after I broke away from him. He said, 'F***ing kill you b****,'" she testified.
Asked by her lawyer whether she was convinced Alexander intended to kill her, Arias answered, "For sure. He'd almost killed me once before and now he's saying he was going to." Arias had earlier testified that Alexander had once choked her.
But Arias' story of the death struggle ended there as she told the court that she has no memory of stabbing or slashing Alexander, whose body was later found with 27 stab wounds, a slit throat and two bullets in his head. She said she only remembered standing in the bathroom, dropping the knife on the tile floor, realizing the "horror" of what had happened, and screaming.
"I have no memory of stabbing him," she said. "There's a huge gap. I don't know if I blacked out or what, but there's a huge gap. The most clear memory I have after that point is driving in the desert."
Arias said that she decided in the desert not to admit to killing Alexander, a decision that would last for two years as Arias lied to friends, family, investigators and reporters about what really happened in Alexander's bathroom.
She eventually confessed to killing her ex-boyfriend, but insisted it was self-defense.
"The main reason [for lying] is because I was very ashamed of what happened. It's not something I ever imagined doing. It's not the kind of person I was. It was just shameful," she said. "I was also very scared of what might happen. I didn't want my family to know that I had done that, and I just couldn't bring myself to say that I did that."
"From day one there was a part of me that always wanted to (tell the truth) but didn't dare do that. I would rather have gone to my grave than admit I had done something like that," she said.
Copyright 2013 ABC News Radio