Of course, Gortash had heard about the arrest, since the Flaming Fist are in his pocket, and when a notable arrest is made, then he knows about it. He's aware of the murder in the temple, and he's more than sure that Orin and her cult are behind it. He also has a hard time believing that Orin would get herself arrested, and that her followers probably have measures against getting arrested.

Thus, here he is, going down into the prison to see the offending party for himself, the Flaming Fist guards letting him through after he pulls rank. He needs a moment before he recognizes the scarred man as the priest who was allowed into the goblins' stronghold. They didn't exactly talk during any of Gortash's visits there, but the man was rather hard to miss among the stout creatures.

"So, I see you survived the massacre at the goblin stronghold."