I'd like to add my few cents worth here too. This thread seems to be running under the impression that this man disobeyed instructions from uniformed police officers. This is not the case. They were plain-clothes police. If I had a bunch of guys with guns yelling at me, I'd probably run too. Uniformed police are a different matter. Also, please remember the British general duties police are unarmed. Yes, police don't carry guns in the UK, unless they're special response police.
Britain, unlike the US, does not have the death penalty. Killing someone, particularly an innocent person, whilst not something unsettling for many in the US, is deeply disturbing for those of us from jurisdictions where taking a life is not acceptable regardless of who does it. For police to shoot an innocent man 8 times in the head is a terrible execution style killing. It may have been a mistake from nervous, gung-ho anti-terrorist police, but the fact remains that an innocent man was killed by an instrument of the state. If you are happy to put up your hand as say 'I am prepared to be killed by police accidently if it means higher levels of security can be enforced on behalf of the general population', then you have a more morally defensible position to not be too upset by this event, because at least you wouldn't be a hypocrite. But if you are not prepared to give up your life, why should someone else give up theirs?
It's easy for people to judge this man based on their own cultural precepts. But he was a Brazilian, from a tropical climate living in a cool climate (and as an Australian who has lived in London, I laugh at what Londoners call 'sweltering' weather), so what he was wearing may not have been that unusual. He had a bunch of guys in suits waving guns at him yelling at him in a very jumpy city. What would you do if a bunch of guys in Sao Paulo started waving guns at you and yelling at you? Did Jean Paul really deserve to be killed for that?