Shawna Ventura miraculously survived the horrific crash and was rushed to Harborview Medical Center, where she's currently recovering from her injuries.
Ventura passed out behind the wheel, and the last thing she remembers is driving home after running a few errands.
"I remember they were calling my name and I remember waking up and being in the driver seat with my head this way and the tree literally on top of me here," she said.
Witnesses say the 43-year-old drove right off the road. The tree that shot through her window missed her, but it was her own seat belt that nearly killed her.
"Her face started to turn color, to blue and purple," one witness said.
A truck driver named Urban Melander was in the right place at the right time and with the right tool. He was driving behind Ventura, and after the crash he pulled over and used a pocket knife to cut the woman's seat belt.
"Walking up to that car I was really scared," Melander said. "She was crammed underneath the tree."
Using his knife, which had been a Christmas gift, Melander cut the seat belt and heard Ventura take a huge breath.
In an ironic twist, the horrific crash may end up saving Ventura's life.
"(Doctors) ran a CT scan to see if I had a head injury and found that I have a growth growing in the left side of my brain," she said.
She believes that growth may be the reason she passed out behind the wheel on Monday.
"I've been chronically tired lately and I think that has to do with what they found," she said.
Melander said he's just glad he was there and ready to help, but Ventura believes she might not be here today if hadn't stepped in.
"I really need to tell him, 'Thank you for my life. Thank you,'" she said.
Ventura was released from the hospital on Wednesday and said she's waiting on results from a biopsy.