@Esme "What's needed is for the legal framework to be in place to allow police (and if necessary, medics) to intervene earlier."
The police obviously have enough powers to shoot dead without warning a completely innocent electrician (Jean DeMenezes) who had not behaved even slightly suspiciously, because he was mistaken for a *suspected* terrorist. The person in charge of that operation was promoted. Exactly what additional powers would you like the police to have? Or is a public execution insufficient "intervention" in your eyes?