Because of how these stories are ordered, the tagged location for that last panel is “Ruth’s high school.”  In addition to Billie and Walky attending it when they came of age, somewhere in that school during that flashback are also Beef and Howard and Dorothy.   I suppose I could rename it now as “some Evansville high school” to be more inclusive, but eh.  It’s the Ruth-Anne Lesse Memorial High School now.  Even though she’s not dead yet.  I mean, she is, but not during the flashback.  Unless they reeeeeeeeeeally missed her when she left for college.