Re: Use case
"Or take the easier option - torch a dozen ambulances and cause a lot more deaths."
That's a blunt tool with a different type of outcome. The scenario you responded to is directed at an individual, probably with a specific reason. Your scenario is not directed at a specific target, but catches random others. To me, it would be part of a disruption of society, and, though I never use the term lightly*, would probably be classed as terrorist action.
*For example, I spent several minutes swearing at the TV for classing a Fiesta driver's actions as "terrorist" simply because of location and skin colour. Morons.