Assemblywoman Shannon Grove, R-Bakersfield, said she, her husband and state Sen. Jean Fuller, R-Bakersfield, were seated at a table with Larwood and her husband when she started choking on Monday.
Grove said her husband ran to Larwood and tried to perform the Heimlich maneuver. He called for a doctor and Johnson attempted the technique as well.
"She had already started turning a real like blue, her fingers and her lips," Grove said.
After the Heimlich failed to open Larwood's airway, Grove called 911 and said she watched in amazement as Larwood was laid back in a chair and Johnson used a friend's pocket knife to make an incision in her throat.
"He didn't scream; he just said, 'I need a knife,'" Grove said.
As several physicians gathered around Larwood, someone called for a pen which Johnson then broke in half and inserted the hollow cylinder to use as a breathing tube.
Earlier Monday, Johnson had appeared on stage at the symposium with Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention (CDC), and Dr. Francis Collins, director of the National Institutes of Health.
All three were at the restaurant Monday when Larwood began choking. As Johnson tended to Larwood, Frieden monitored her pulse.
"I was sort of looking at her breathing, Royce is blowing into this tracheotomy that he performed and the CDC director (Frieden) is checking her pulse," said Dr. Paul Krogstad, a professor of pediatrics and pharmacology at UCLA. "(Larwood) came around."
The procedure was successful as Larwood was rushed to a hospital. Her son said Tuesday that Larwood, a former Kern County Supervisor, was doing fine.