"At first I didn't feel in danger until I saw a large group of them waiting at the entrance door as if they were monitoring who was walking in and out," she said.
There was then loud yelling coming from outside, followed by a gunshot, the sound of which was also captured during a recorded interview taking place in the area.
"We were feeling terrified and my sick children were in tears," the woman said. "We were then told the medical centre was on lockdown until police arrived."
A source told Hawke's Bay Today a youth was bashed near the ramps in Anderson Park, Greenmeadows, during the afternoon, but there had been other standover incidents there recently.
Police district crime manager Detective Inspector Mike Foster said police were called to the park about 3.15pm, when a group of men were reported to be fighting.
One person injured at the park was taken to hospital with injuries that weren't regarded as life-threatening.
About 6.10pm, a gang member was struck by a car in Geddis Ave, sustaining minor leg injuries, soon afterwards a gang member arrived at the medical centre with a stab wound, and later police were called to the centre where a shot had been fired, hitting a front wall between the main entrance and the Heart Foundation offices, but no one was struck by the blast.
"It is fortunate that no innocent members of the public were injured in any of these incidents," Foster said, a point amplified late on Monday by gang-relationships expert Denis O'Reilly, who said said it was "a miracle no one got really hurt".
Foster said Napier people might notice a heightened police presence in the community as inquiries continued, and police wanted to hear from anyone with information about the incidents.
Napier Mayor Kirsten Wise said she was "shocked and saddened" by any escalation of violence in the community and said the Council would support police and other community agencies working to resolve gang related incidents.
A DHB spokeswoman said it was also working closely with police. The Health Centre was open on Monday. Police still had a cordon up and were photographing the scene at 9.30am.
O'Reilly pointed to some need to address gang-related issues, amid some breakdown of positive issues of the past.
A meeting of gang leaders from different factions in 2011 adopted the Otatara Accord, which he said had been "powerful and worked pretty well", and there was a need to "divert, contain, redirect" by working "peer-to-peer" with young people gravitating towards gangs.
On Monday afternoon one man was reported in a stable condition in Hawke's Bay Hospital.