Probably just that they saw heavy fighting and were the ones who survived through it. How many Soviet snipers died after only a few, if any, kills? Obviously any of them who were successfully killing Nazis were very skilled shots, and managing to survive showed off strategic intuition and other skills too, but there's also just the sheer scale of the conflict and how many chances there were for individuals to be lucky or unlucky with how shells fell or who looked what direction when.

Like there are so many insane stories about almost superhuman actions or luck just as a function of how absurdly huge and all-encompassing the war was. You have cases of airmen falling without parachutes and surviving impact with the ground, because there were so many people who fell like that that some got lucky and had something break their fall (one Soviet pilot simply hit the side of a hill while unconscious from a lack of air, and rolling down it at speed slowed him down enough slowly enough that he wound up with only minor injuries and was back in the air within a few months, for example). You've got soldiers losing limbs and still charging and taking fortified positions, or using their own severed limb as a blunt weapon to keep fighting, just because out of the millions of soldiers to be grievously injured or killed in combat a few were so keyed up with adrenaline that they ignored mortal injuries to keep fighting.