An Armed Offenders Squad (AOS) member also told the coroners court victims were left alone in the mosque for 10 minutes while officers stood guard outside, because they believed the threat of a further attack was too great to remain inside and help.
A total of 51 people were killed and many others injured as a result of the attacks on Al Noor Mosque and Linwood Islamic Centre on 15 March 2019.
The gunman left the Deans Avenue mosque at about 1.45pm on the day of the massacre.
CCTV footage played to the court shows the first two paramedics did not enter until 2.14pm, under the protection of armed police.
On Tuesday, the inquest heard injured man Zekeriya Tuyan was on the phone to emergency services from inside the Deans Avenue mosque for more than half-an-hour before paramedics went in.
Tuyan became the 51st victim of the terror attack when he died from his injuries on 2 May 2019.
On Wednesday, another AOS member, whose identity is protected, said he stood guard outside Al Noor Mosque after clearing the building.
He said there were no police staff in the mosque after a team left for the Linwood Islamic Centre, where more shots had been fired, and before armed officers took paramedics in 10 minutes later.
The AOS member told police lawyer Mark Zarifeh that he was focused on the risk of a further attack, even though he wanted to go inside the mosque and help the injured.
The court has heard evidence about police radio calls about a vehicle returning and another nine offenders in Christchurch targeting mosques because of false information the terrorist gave arresting police.
"My thought process was that the priority was the risk of if I was inside the mosque, then there was no-one outside protecting us while we were trying to deal with the victims inside," he said.
"Hence, I deemed the priority was of protecting the mosque as best as I could."
The AOS member said he was frustrated around 2.10pm when he could see two ambulances further down the street who were not coming forward and soon drove off.
He did not realise at the time that they were treating victims at a nearby location and transporting them to hospital.
The scene on Deans Avenue was "chaotic", he said.
"Even though I had been involved in a number of critical incidents in the police, it was the only time in my career that I thought this was my last day due to the threats that existed at the time."
• the events of 15 March 2019 from the commencement of the attack until the terrorist's formal interview by police
• the response times and entry processes of police and ambulance officers at each mosque
• the triage and medical response at each mosque
• the steps that were taken to apprehend the offender
• the role of, and processes undertaken by, Christchurch Hospital in responding to the attack
• coordination between emergency services and first responders
• whether the terrorist had any direct assistance from any other person on 15 March 2019
• if raised by immediate family, and to the extent it can be ascertained, the final movements and time of death for each of the deceased
• the cause of death for each of the victims and whether any deaths could have been avoided
• whether Al Noor Mosque emergency exit door in the southeast corner of the main prayer room failed to function during the attack and, if so, why?
The inquest continues.
