My Fiancee Was Falsely Admitted Into A Psych Ward Due

My fiancee was falsely admitted into a psych ward due to someone lying saying she ran off with pills and wanted to kill herself, of which I know to be false because she was with me when she apparently did that. The psych doc won't believe her, me nor our roommate about her being okay and won't let her out without either an outside psychiatrist clearing her or her admitting to doing it (lying) so proper treatment can begin. What do I do?