I'm assuming that the OP made a mistake in stating that the F# is so loud as to be perceived as a voice of the motive, since I've never heard this ever before, which is why I made the remark about the different rhythms. Barenboim did, indeed, alter the rhythm and delay the downbeat as a result. My previous statement still stands. By tomorrow morning, he will be fingerless, armless, and will be found next to horse manure.