His safety is a concern because we’re dealing with royalty here. Aside from him not knowing this world’s norms for dealing with nobles in general, which in and of itself may lead to punishment if he accidentally offends somebody, he’s dealing with the princess here, where anything could lead to his execution. In fact when he served the mapo tofu he was nearly killed on the spot because it was spicy. So guaranteeing that their cook, which at this point the group can’t live without, stays safe regardless of his manners would be in his best interest.