Apparently, it's a squad of Russian Soldiers refusing to go back to the front line. The fat guy says they were NOT getting food or water (yeah I heard it), I am pretty sure he is right. So, what are the types of conditions you have to face to get water and food at soldiers? I mean, I can understand them not getting ammo and man power to get rid of the dead. Probably manufacturing problems and it's dangerous respectively. But yeah, what else? Why would they not get food and water?
Cutting the supply lines is one of the most classic military strategy. In most armies there is way more soldiers involved in logistic and support than soldier actually fighting. If you want to get rid of the soldier fighting on the front-line you can send other soldier fighting against them, but they are trained and ready to fight or you can just cut the supply lines by destroying bridge and bombing supply truck/trains. During Napoleon's Russian campaign (people will start to believe I am obsessed with Napoleon) russia did burn the crop before withdrawing, and it's how once they reached Moscow the soldier had no food left and Napoleon's great army died from starvation while retreating under Russian winter