MARIUPOL, Ukraine (Reuters) – In Mariupol daily life is a series of harrowing escapes from bomb blasts and basic survival rituals, amid the rubble that lies everywhere. Uncollected corpses wrapped in blankets, coats or any available covering lie in courtyards cleared of debris. Those killed are often buried in common graves. All around are the blackened shells of the sprawling tower blocks typical of Soviet-era dwellings. Twisted metal on balconies, shattered windows, woods, metal and other wreckage scattered between buildings and in streets. Some 400,000 people have been trapped in the strate…