DONETSK OBLAST, Ukraine — The ambulances hurtled into the parking lot one after the other, each carrying wounded troops directly from the nearby front line. One young man stared straight ahead, his face swollen, his neck and back dripping with blood. Others lay silently under foil blankets.Some stumbled out the back doors and collapsed into wheelchairs as staff rushed to push them inside. Nearby, bloodied cots sat propped against a tent and other wounded soldiers lingered about, their faces grim, their heads, arms or legs bandaged as the sound of outgoing artillery boomed across the sky.About 10 wounded soldiers arrived...