Proper use of firearms in Britain
According to the London paper The Times Online, onlookers to the recent shooting of the fleeing bomber in London describe the situation as:
"He sort of tripped but they were hotly pursuing him and couldn’t have been more than two or three feet behind him at this time He half-tripped, was half-pushed to the floor.
"The policeman nearest to me had the black automatic pistol in his left hand, he held it down to the guy and unloaded five shots into him."
The British (for all their gun law failings) have long had a more realistic response to terror than we do. When I was with Interior in the late 80s, another attorney attended a terrorism response session (yes, they had concerns back then) where there was a presentation on the British storming the Iranian Embassy, which had been taken over by hostage-takers. He said the SAS had been given photos of many of the hostage takers, and told they were divided into three classes. One, I assume needed for interogation, were to be taken alive if at all possible. A second group could be taken alive or not. A third group was not to be taken alive, period (I assume because future hostages might be taken in order to free them).
The hostage takers had taken a British policeman. Since they supposedly aren't armed, they didn't search him. Well, British cops don't always follow that rule, and he had a hidden gun. As the SAS stormed the building, he grabbed a hostage taker and put the gun to his head. The SAS burst in, and he shouted he had the fellow. The SAS ordered him away from him. He stepped away, and they shot the hostage taker dead. He had been on the third list.
I'd assume there was no such list involved here, but the concern would have been whether the fellow had a bomb belt on, and a warning shot to the head was the best solution. It doesn't sound like there was a detailed investigation -- but with a city under repeated terrorist attack, a fellow who attracts police attention, flees, and rushes into the subways which have been a target in the preceding days and indeed hours, does assume a certain risk.