Tim Bowen is on fire again with this hot selection of idioms.
When there is a riot, buildings may be on fire and people may set fire to cars and loot shops.
Afterwards, the police may come under fire (be severely criticized) for their handling of the riots and may draw fire (attract criticism) from a number of political leaders, in particular. However, senior police officers can hit back and fight fire with fire (criticize their critics) and it is likely that some senior politicians will be next in the line of fire (likely to be criticized for their words or actions).
Sometimes in these situations, of course, it is better to hang fire or hold fire (wait before taking action) and opening fire (starting to shoot at) on the rioters would probably add fuel to the fire (make a bad situation worse) and would surely have disastrous consequences.
The police often have several irons in the fire (a number of different plans) for dealing with any repetition of this behaviour and say that anyone contemplating doing so would be playing with fire (doing something dangerous or risky that could bring them problems).
Clearly, images of riots on television fire the imagination of a number of people (make them extremely excited) and fired with enthusiasm (full of enthusiasm) they join in the looting and burning. In fact, it may seem that many of the rioters are firing on all cylinders (putting in a lot of energy and effort) as they grab armfuls of goods from the burnt-out shops.