BEIJING—American mixed doubles curlers Vicky Persinger and Chris Plys survived an extra end against Sweden for a much-needed victory in the Olympics on Friday, quickly hugged and then found two friendly faces to wave to in a far corner of the eerily quiet and mostly empty Ice Cube. Masked faces, of course, but definitely friendly faces. Persinger and Plys were pretty sure they were waving at team psychologist Carly Anderson and dietician Kaela Colvard, who were among the few spectators who saw the Americans take an 8–7 victory in the round-robin competition to even their record at 2–2. “It’s hard to tell with the masks on. I think it was our sports psychologist and our dietician who were in the stands,” Persinger said. “They’ve kind of been around our team and were cheering us on especially coming back after a two-loss day.” Every little bit helps in these Games, which …