Jason Anderson, a combat medic stationed out of Joint Base Lewis-McChord, saw the woman and her grandson crash into a stump in the middle of the river, he said. Their inner tubes were tied together by a rope that got tangled in the roots, he added.
"She was in the water and holding on to the tube with her arm like that," Anderson said.
A witness jumped in and somehow got the tubes untangled, Anderson said. The woman slid through her inner tube and started floating downstream, he added. As soon as she grabbed on to a set of branches, Anderson and another man swam over to a log hoping to catch her as she passed by.
"As I seen her let go, I pulled myself up and told the grandson to get to shore," Anderson said. "I tried to grab her as she was going by me and I missed. I didn't get her arm like I was going for."
Anderson said at that point it was simply too dangerous to continue on. He watched as the woman got trapped in some roots from a fallen tree downstream.
Some witnesses were able to reach her by boat, investigators said. They pulled her out of the water and started to perform CPR, they added. As soon as they reached the shore, medics took the woman to the hospital, but it was too late. She did not survive.
"The hardest part is the point where I knew there was nothing else I could do. And I just had to sit there and watch knowing that she's under the water and I couldn't do anything about it," Anderson said.
Anderson said his heart breaks knowing the woman did not survive. The Thurston County Coroner identified her on Monday afternoon as Ilona Mohs-Peissner, 58, of Lacey.
Anderson said he knows he and everyone else who came to the woman's rescue did everything they could to try to save her.
"If anyone else was out there and it was my grandmother or my children, I wish they'd do the same thing. That's why I did it," Anderson said.
Investigators said the teen made it to shore on his own. He and his grandmother were not wearing life jackets, they added.
An autopsy on Mohs-Peissner's body is scheduled for Tuesday, the Thurston County Coroner said.