The woman, a staff member at Oamaru Hospital, said a man pulled a knife on her in a "dark spot" of the hospital carpark as she left work on Tuesday night.
After unlocking her car and putting her handbag on the back seat, she turned to shut the door and a man suddenly appeared and asked: "Can I see your car keys?
"I thought, ‘that’s really, really odd’.
"It was so strange and I started to get a wee bit nervous," she said.
The woman said the man then said "give me your keys or I’ll stab you".
"He scared the living s... out of me.
Frozen in fear, she said she was like a "stunned mullet".
"I thought, ‘is this really happening?’ He smashed the keys out of my hands and, when they landed on the ground, I just ran and ran, screaming ‘somebody help me, help’."
The woman ran to the hospital emergency department, where a co-worker rushed out and chased the man.
She called out to him, "watch out, be careful he’s got a knife".
She said she had just been talking with work colleagues about the Sydney stabbings before leaving work and could not believe what happened.
"Then to go out and that to happen, I thought, ‘is this some kind of joke?’
"It could have gone so different; it could have gone very badly," she said.
"I felt like I was alone with it all ... When I got to the hospital afterwards, the staff were amazing — they all dropped everything to help me."
Now a day after the event, she felt sorry for the man, she said.
"What sort of life has he had and what is life going to be like for him?"
Senior Sergeant Jason McCoy, of Oamaru, said after the woman was allegedly held at knifepoint the 23-year-old man then went on foot to a neighbouring carpark.
"He has then stolen another woman’s vehicle and driven off," he said.
A man was "stopped shortly after on Thames St by a police officer and taken into custody without incident".
Fortunately, neither woman was injured, Snr Sgt McCoy said.
"There is no place for this activity in our community."
The 23-year-old man taken into custody had no fixed address in the South Island and had arrived from the North Island during the past two weeks.
He had been remanded in custody till May 15.
Oamaru Hospital interim joint co-chief executive Andrea Cairns said she was grateful the police apprehended the alleged offender so quickly after the incident.
"My concern was for the staff’s safety and her wellbeing."
The staff member was taken to the emergency department for assessment and Mrs Cairns spoke to her and all the other staff about the incident.
"Considering the circumstances, she is doing remarkably well. It could have been a lot worse."
There had not been any problems with staff safety before when they returned to their cars, she said.
"We do have internal security measures in place, duress alarms for staff that they wear around their necks that alert police if there are any incidents within the building.
"Unfortunately, in this case, the staff member was leaving the building."
The carpark was well lit and staff were encouraged to walk to their cars in groups at night, she said.
There is security footage of the carparks.
An email had gone out to Oamaru Hospital staff informing them of the event and offering support, Mrs Cairns said.
