I think you are on the money, but I think there is a bit of mockery going on but not in like a “mocking the people” that choose the religion.

He is talking to extremist radical islamists, not peaceful Muslim civilians.

He is giving them a last olive branch and almost saying like “look I will speak your language, if it’s Allah you pray to then you better take this deal now, in Allahs name or you will burn in hell.”