Orphan Black Season 4 episode 6 spoilers: Cure for Cosima impossible? Sarah to surrender Kendall?

Orphan Black Season 4 episode 6 airs tomorrow night, and the plot thickens with the shocking events that happened in the previous episode. The upcoming episode's synopsis states that there may not be a cure for Cosima (Tatiana Maslany) after all. Meanwhile, Sarah will expose Kendall (Alison Steadman) to their enemies.