disclosure: a certified crazy person emailed me the below (so this amounts to me posting someone else’s speculations):
Rule 14. Relief from Prejudicial Joinder
(a) Relief. If the joinder of offenses or defendants in an indictment, an information, or a consolidation for trial appears to prejudice a defendant or the government, the court may order separate trials of counts, sever the defendants’ trials, or provide any other relief that justice requires.
(b) Defendant’s Statements. Before ruling on a defendant’s motion to sever, the court may order an attorney for the government to deliver to the court for in camera inspection any defendant’s statement that the government intends to use as evidence.
Notes
(As amended Feb. 28, 1966, eff. July 1, 1966; Apr. 29, 2002, eff. Dec. 1, 2002.)