MEDYKA, Poland—Anna Gorpenich and her two children left the war-struck city of Sumy in Eastern Ukraine when the first safe-evacuation corridor arranged with Russia was opened. Forty hours later, on the afternoon of March 10, the family arrived alongside thousands of Ukrainians streaming into Poland at the border crossing in Medyka. Sumy is one of several cities on the frontier of the Russian invasion in Eastern Ukraine. Russian tanks rolled through the streets of Sumy on February 24, the first day of the war in Ukraine. The surrounding areas have seen ongoing fighting since. Gorpenich said the situation in Trostyanets and Okhtyrka, two smaller cities south of Sumy, is particularly dire. The residents don’t have heat, water, or electricity. “They have nothing. Today they were supposed to open a safety corridor and the people, including our friends with two children, they were supposed to be able to evacuate, but Russia …