That armed officer would have a very very difficult decision to make and weigh up in matter of seconds, probally less.
He would have known that the man had stabbed people. He would have known that he had a knife and some reports say he had Two knives taped to his hands so it was very difficult to disarm him.
Another report said that he did have a gun in a bag an then there was the fake vest. Now who on here has ever seen a photo of that sort of item other then on a TV programe?
I could if i wanted make something that looked very dangerous some old bog rolls painted red or grey stuffed with paper painted up and a few wires or electic flex commng out of them. Who would know if that was live or not?.
Now he could have, if desired, disabled that man with a few shots to the lower torso after all he might have held valuable intellengence that would have been worth knowing to the security services perhaps.
Now he would have also known that others were in damage range of a bomb like this and himself. He wouldnt be able to know if that was real or not
So he has to decide to shoot to kill all in a second or so.
What would you do, anyone?..