The American decision to threaten Russia might simply have been a last-ditch attempt to force Tehran's hand now that conciliation seems to have failed. It isn't likely to work, because for the time being Russia has the upper hand in the former Soviet Union, and the Americans and their allies -- motivated as they may be -- do not have the best cards to play.
So if the military option comes about, October 25, 26 may wind up being the turn point into that per the web bot's computations.
The other explanation might be that the White House wanted to let Iran know that the Americans don't need Russia to deal with Iran. The threats to Russia might infuriate it, but the Kremlin is unlikely to feel much in the form of clear and present dangers. On the other hand, blasting the Russians the way Biden did might force the Iranians to reconsider their hand. After all, if the Americans are no longer thinking of the Russians as part of the solution, this indicates that the Americans are about to give up on diplomacy and sanctions. And that means the United States must choose between accepting an Iranian bomb or employing the military option.