Then the immunity is not in effect any longer, silly. Or it wasn't a 100% immunity to begin with.
That is normally how immunity agreements are written, but in the case of the immunity given to Hillary's minions it didn't require that they testify or tell all. The were given blanket immunity then asked if they would cooperate which they chose not to do, in fact what they did say turned out to be proven lies. Under a normal immunity agreement, the immunity would be revoked, but these couldn't be revoked so they will never have to face prosecution unless new crimes are proven that weren't covered in the immunity agreements. Thus the outrage from so many in law enforcement, they had never seen such blanket immunity agreements where no matter what they did or didn't do, they had immunity from prosecution.