Didn’t see the movie, but could it have been napalm? Altho jellied when put in the bomb, would it liquify after so much time inactive?
Drinking napalm would make you very sick to say the least, especially the modern formulation which uses benzene, gasoline and polystyrene, although WWII-era napalm was made with naphthenic acid (MSDS, not extremely toxic with a LD50 similar to table salt (3g/kg) but probably foul-tasting and would make you sick at much lower levels) and palmitic acid (a saturated fat commonly found in food). **sitchensis **already gave the most likely answer, which is ethanol (possibly denatured, but that didn’t stop people from actually drinking it).
TVTropes (always a reliable source of factual information) has a claim that the Russians started requiring their truck fuel to have a higher alcohol content so that when the soldiers inevitably drank it to try and get drunk, that they would have a higher chance of succeeding before they poisoned themselves.
Meanwhile, I have been told buy a guy who was in the Army (an equally reliable source of information) that the reason they no longer include dehydrated fruit in MREs is because if you put it in your canteen with sugar and water, it would ferment and make hootch. Also supposedly why the canteens are all marked with “USE WITH WATER ONLY”