Grand juries are not part of the judicial branch of government for a reason. They are the People's checks and balances. Restore justice, faith, and confidence in our government by abolishing rule 6 of the federal rules of criminal procedure, and restore the constitutional purpose of grand juries.
A grand jury panel should be the grand jury, determining whether it will or won't investigate/indict.
There is no such thing a "runaway grand jury", unless a prosecutor could also be considered a "runaway prosecutor" for signing and filing an information without prior judicial approval.
A prosecutor can prosecute a so-called "ham sandwitch" with a grand jury just like they attempt on their own. A prosecutor can not convict a ham sandwich.