WARREN, Mich. – An employee at the GM Tech Center in Warren was stabbed multiple times Wednesday morning when she was attacked outside a lobby allegedly by her own daughter.

Stephanie Kerr, 52, was called down to the lobby after a 32-year-old woman asked for the employee by name. Kerr’s family says the woman was her daughter.

When Kerr came down to the lobby, the two women went outside and the employee was attacked with a steak knife.

"It's very difficult because it just brings tension between the family," Matthen Kerr, the victim's son, said.

Kerr's family said the daughter suffers with mental health issues and that doctors had taken her off medication about three months ago because they thought she was doing better.

Paco Sarder, a valet who is a licensed gun holder, saw the attack and used his gun to hold the suspect until police arrived.

“There were people around, but she had a knife,” Sarder said. “I guess people were afraid to stop it. They didn’t want to get hurt.”

He said he was acting on instinct.

WATCH: Priya Mann talks to Paco Sarder

“My natural instinct was to unholster my firearm and I pointed it at her and I told her to drop the knife,” Sarder said.

The victim suffered life-threatening injuries to her neck, stomach and back. She is in critical condition at Beaumont Hospital.

The suspect is in custody.

“If I didn’t pull out my firearm, the lady would not have lived.” Sarder said. “It was the right thing to do. Someone is dying in front of you, you’ve got to do something. I would have felt like a coward if I didn’t do anything.”

Sarder was escorted off the property by GM security officials. He did not lose his job at the valet company that is contracted by GM, but was told he is not allowed to work at the tech center because he was carrying a gun on company property.

"I'm very thankful for him saving my mother," Matthen Kerr said. "I don't know exactly what I'd do without my mom and it's just me and here here at the moment. I'm just really thankful that he stepped in and saved her."