I'm a Trained Observer

A few years ago, during a weekend late shift which runs from 5pm to 3am, I was part of a van crew of about half a dozen officers.
We were called to a "disturbance" at a house which was only about two hundred yards from the Police station. Now "disturbance" can mean anything, from full blown fight involving several people, perhaps with weapons, to a couple arguing over who lost the remote control. Whilst you're on your way to such a job you've got no idea what you're going to be facing when you get there. And, I have to be honest, this is part of the attraction of the job.
So, we volunteer to attend and arrive there from the town centre where we'd been watching drunk people falling over within a couple of minutes.
We pulled up outside the house and I could see, straight away, about five or six people at the front door shouting and screaming at each other. You get a feel for this sort of job fairly quickly and automatically learn to look for things like injured people, whether it looks like a fight or an arguement etc. This job looked very much like half a dozen people trying to out-shout and out-point each other. Nothing too exciting but it needed splitting up before it got too out of hand.
We all ran from the van, up the garden path and started pulling people away from each other, standing in between them and trying to calm them down. In the minute or so that this took I was vaguely aware that there was another person stood in the garden, about five yards away. This person, a bloke roughly in his fourties, wasn't doing anything other than watch what was going on. Clearly no threat to me or my colleagues I basically ignored him and concentrated on the job at hand. I thought he was a bit rude him staring like that maybe, but hey, it's better than most of the stuff on TV. Turns out he was also from the house but apparently didn't want to get involved in the sillyness outside.
We got the warring parties inside the house and tried to work out what had caused the disturbance. After a few minutes, one of my colleagues said to the Sergeant "I'm sure that bloke was holding something outside".
He went back out to the garden and with his torch started to look around where the man had been stood. He later told us how he peered over the hedge where the man was and saw, lying on the ground, a loaded, sawn-off double-barrelled shot gun. He quickly pointed this out to the Sergeant and the man was searched. In his pockets were a load of other shot gun shells.
He was arrested and the rest of the house was searched by a van crew of Police officers who were suddenly a lot less complacent about what they were doing. We ended up finding more handguns and face masks.
Turns out we'd interrupted a domestic between armed robbers and their wives.
After we'd finished we were all sat down in the canteen having a brew, alternating between nervous laughter and stunned silence about the job where we all ran past a dangerous armed criminal completely oblivious to the shot gun in his hands.
Like I said, Trained Observer...