A senior firearms officer ordered his team to be "on top of their game" just before a police marksman shot dead suspected armed robber Azelle Rodney, a court heard.
The operation's Bronze Commander gave a dramatic account of events leading up to the moment police firearms officer Anthony Long blasted 24-year-old Mr Rodney six times during a "hard stop" in Mill Hill, north London, 10 years ago.
The officer, identified only by call sign E1, was screened from view by journalists, but could be observed giving evidence in the murder trial of Long by the jury, defendant, lawyers and family of the victim.
He told the Old Bailey how on the day of the shooting, the suspects had already been under surveillance for some time and it was believed they were armed with an automatic weapon and were on their way to carry out a robbery on a group of Colombian drug dealers in Edgware, north London.
The four-car convoy of firearms officers set up to support surveillance had been parked in Harlesden, north London, when they were told the suspects were on the move.
E1 told the jury that a "static interception" in Harlesden had already been ruled out because there were too many people around and the suspects could easily escape, being familiar with the area.
During his 6pm briefing - an hour and three quarters before the shooting - he told his men to be "at the top of their game".
He said: "I told the teams it was believed the suspects had possession of automatic weapons and were seeking access to another.
"They were intending to use them in a robbery and the threat was greater than we were used to deal with. I wanted the team to appreciate the risks in any interception of the suspects.
"It was my way of telling my team 'guys, this could be really risky, this could be dangerous, we want to act accordingly and make sure we are on the top of our game when we deal with this'."
He said Long - call sign E7 - was to provide "static cover" during the operation because of his position as the front passenger of Bravo car which would pull up alongside the target Volkswagen Golf.
Beforehand, they agreed he would wear a ballistic helmet marked with a police badge for protection, E1 said.
By 6.30pm the Golf was reported to be leaving Harlesden and the firearms team followed at a distance along the A40, into Mill Hill Broadway and Hale Lane where E1 ordered a "state red" to initiate the stop.
He said: "It was significant for me in so much as it was the first opportunity to effect state red for some sort of interception. The other roads were not ideally suited, they were too busy.
"It was possibly the only opportunity to carry out an interception before we got to the Edgware area - where we believed the Colombians were."
After the stop, E1 got out of his vehicle at the rear of the convoy shouting "armed police" and ordered a group of people sitting outside a pub nearby to move inside.
He said: "As I approached these people I heard a succession of shots ring out from the vicinity of the Golf. I instinctively thought they had come from an automatic weapon.
"I ran to the nearside of the Golf just past the entrance to the pub. Armed officers were covering the Golf. I continued to shout 'armed police'.
"The group of people were getting under a table seemingly in response to shots being fired. I shouted 'Police! Get inside the pub.'
"Once I was satisfied the people outside had gone in, my attention was focused towards the Golf. I could see E7 covering the rear nearside window. He was out of the car."
Another officer - E3 - opened the Golf door to reveal Mr Rodney slumped in his seat, E1 said: "I saw a black male slumped in the vehicle. I could see he was not moving and blood was spilling out of his head down his body.
"I shouted words to the effect 'get him out of the car and start working on him'.
"I asked E7 if he was alright and he said he was and I asked him to sit in the control vehicle and that's what he did. "
Later, he went to speak to Long in the car, he said: "I asked him if he was okay and what happened. He told me that he fired at the male suspect believing he was going to fire a gun. That was sufficient to know he was the officer who fired the shots. He was shocked but otherwise okay."
When he went back to the suspects' car, E1 said: "I looked in and saw a black self-loading pistol on the seat. It was partially covered by a bloodstained item which was yellow. I also saw several bags in the footwell. I know it transpired there were weapons."
Long, 58, who has given an address in Leatherhead, Surrey, denies murder and the trial continues.