From a procedural standpoint - could Muller already have subpoenas and/or indictments sealed and in-hand and not need Whittaker’s approval to issue the subpoenas or charge on the indictments? Once a grand jury has issued a True Bill can that fact, itself, be kept secret at the discretion of the (acting) AG? If not, and the AG chose to simply dismiss the charges (I assume that is within his powers), I’d think the fallout would be pretty substantial.