At about 3:15 p.m., patients and medical staff evacuated after hearing a gunshot on the second floor of the Serramonte Medical-Dental Building on the 1500 block of Southgate Avenue.
"Scariest thing I've ever been through," Shirley Snead, a doctor's office employee, told CBS News. "It just was really loud and I was talking to a patient at that time and I said to her, 'Oh my God did you hear that?' Next thing that I know, we're on lockdown."
The SWAT team surrounded the facility as patients and staff evacuated. Police reportedly went room-by-room, looking for the shooter. The news station later reported that the shooter had been targeting a doctor named Kevin Wong.
The doctor saw the gunman and ran, dodging the bullet.
Witnesses identified Iwase as the gunman and a disgruntled patient. He was booked on suspicion of attempted murder into the San Mateo County Jail Wednesday night.