I heard it was 5 armed men and that 3 of them were shot. In Britain, for civilians, carrying a weapon in a public place, or anything that could be used as a weapon (with the intent to do so), is a felony.
If 5 enraged lunatics suddenly start hacking people to death with machetes or carving knives and you are close by with your family or partner are you going to go and take them on unarmed? Especially, if one, or more, of them have bomb-like items strapped to themselves.