Crais tortures Rygel by holding his head under water. However, it is established in other episodes that Rygel is amphibious. He should not have been affected the way he was.
When Rygel is flying away from Moya in a transport ship, D'Argo responds to Rygel with luxan words. Crichton asks what D'Argo said, but the "Translator Microbes" in Crichton's brain should have translated what was said.