Racing down a road with his men in pursuit of retreating Russian soldiers, a battalion commander came across an abandoned Russian armored vehicle, its engine still running. Inside there was a sniper rifle, rocket propelled grenades, helmets and belongings. The men were gone. “They dropped everything: personal care, helmets,” said the commander, who uses the code name Swat. “I think it was a special unit, but they were panicking. It was raining very hard, the road was bad and they drop everything and move.” After months of static fighting and holding the line under withering Russian artillery barrages, Ukrainian soldiers...