Stephen Tracey -- "And for 'Outside The Wall' also towards the end in the movie, when the boy tastes the gas from the Molotov cocktale and he makes a face and spits it out, showing he's rejecting it. Molotovs are made for one purpose and one purpose only, to destroy, cause suffering and pain, it's a war item. The boy spitting out the gas could be symbolism that the boy is rejecting this hate and weapon. Showing that instead of building a wall of hate, he's not building a wall, or a "good" wall, trying to block out the pain of war."
Author's Addendum: I think it's interesting that the kid doesn't even go so far as to taste it, as Stephen suggests...he simply smells it before rejecting it and pouring it out. I think it's fairly significant that there's already this degree of separation from his generation and the violence of the past, especially considering that Pink metaphorically drinks the violence and shoots it into his veins before rejecting it and throwing it back up (notice the Judge's excretion at the end of "the Trial"....as if Pink, through his inner judge, is purging himself of it all). One generation later and teh child rejects the bricks of the past by immediately pouring out the petrol bomb just after a quick sniff.
Gos -- "In the video footage accompanying 'Outside the Wall,' you mention the child who picks up the Molotov cocktail. In World War II, children were often recruited in the Allied countries to aid the war effort by gathering and sorting recyclable/re-usable items such as tires, bottles, scrap metals, and other such items. In 'Outside the Wall' we find a young boy engaged in just such a gathering effort, when he finds a Molotov cocktail, whose wick he pulls from the neck of the bottle, sniffs it, and contorting his face in a look of childlike disgust, he upends the bottle, spilling its contents onto the pavement.
In the modern day, we typically tend to think of a Molotov cocktail as being filled with gasoline or diesel fuel, but the liquid in this bottle doesn't appear to have the oily consistency of diesel, and doesn't have the amber color of gasoline. This suggests a third alternative: Alcohol -- a favored fuel for these crude incendiary devices, since it's easy to obtain, and even if not, it can be easily produced using materials that are readily available virtually anywhere. (Hence the name, "Molotov cocktail".) Of course, it's plain to see that The Wall is not merely about alcoholism, and so the Molotov cocktail in this scene (being the very last image we see,) is intended to symbolize far more than mere alcohol abuse. In fact, it symbolizes both the destructive nature of war and violence, and also the self-destructive nature of the drug and alcohol abuse that were surely both symptomatic of, and a catalytic factor in, Pink's decline. Alcohol is an acquired adult taste, and children typically don't like it at all. Likewise, the violence that children see in the adult world must surely appear as madness to them. This scene, therefore, by the juxtaposition of the child and the Molotov cocktail in the frame, symbolizes childish distaste for things that, quite frankly, adults should find distasteful themselves, if they were nearly as wise as children. Inferring this dual symbolism of the Molotov cocktail, it becomes apparent that the underlying message is summed up in the wisdom of a child: "Whether this bottle of alcohol was intended to destroy yourself or someone else, the best thing to do is to wrinkle your little nose in disgust, and just dump it out.
Oh, and recycle the bottle.....at least that way, it's useful for something...."
Darrell Lunsford -- "When the wall finally comes down, I think that it is important to note that the bricks themselves are not destroyed, only the mortar is. The 'bricks' of lifes experiences cannot be undone, but it is the individual that holds them together as a barrier against the world outside. I think that realizing that the bricks remain unchanged is an important point, particularly when considering the cycle intimated by work in its entirety. Even when we find our way out- find the way to tear down our own walls- the materials and propensity for rebuilding will remain. We may find ourselves re-building our own wall, but hopefully finding our way back out by tearing it down again."