S04E20: Deliverance

Diane goes into labor unexpectedly and when no one can find Billy she reluctantly asks Kate to be her coach. Wilkes must get a family to safety from an abusive husband/father. McNeil and Catera take dance lessons (with special guest star Kenny Ortega, who choreographed ""Brain Salad Surgery."" Billy arrives at the hospital and discovers that Diane is having a c-section after her and the baby have gone into distress during the labor.