Calm and asking for care and consideration is the only communication tone to take during an extremely tense and dangerous situation. Especially one being played out in front of hundreds of people. Then, as that audience reached for their phones, the audience rises to hundreds of thousands. 

This article discusses public relations industry praise for those working in the communications team at the Metropolitan police during last week's terror attack on London. 

I've been involved in many major stories during my time as a journalist and I know lots of communication teams follow a professional, planned and practised release of their information,  balancing a number of competing factors.  But we are all human beings and it is impossible to know how news will unfold or predict events, let alone what information there will be available to release to the public.  Briefing the press team isn't always a priority as people lay injured or dying. 

But as this article and many others demonstrate, there was a calm and civilised response to the murderous attack by one person. And that was clearly communicated.