If there was even an ounce of truth in the above, what would that make the UAE, Saudi and other PGCC regimes for entrusting the same US with their defence, for purchasing tens of billions of overpriced weapons from the US, for allowing the US to establish military bases on their soil - the same US which supposedly is empowering their Iranian nemesis? The term vassal states would no longer suffice to accurately reflect their status vis a vis American imperialists.
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To be honest, I doubt this figure has ever been confirmed by a credible source. To my understanding it's propaganda peddled essentially by Iran's enemies and perhaps their domestic fifth columnists in a futile attempt to turn Iranian public opinion against the country's peaceful nuclear program.
As for the OP question, I'd almost be tempted to respond in a single word, let alone five lines, namely: nothing. Iran is overall in a very comfortable situation at the moment, in the geostrategic realm its position is solid and steadfast, enemy plots are blatantly failing one after another no matter how creative or colorful (which they actually seldom are, but well...), development-wise there's steady unabated progress as well, and major oppressors such as the US regime are on the decline. Truly, to this day America couldn't do a damn thing, no matter how hard they tried.
But yes, probably there are specific steps Iran could and should proceed with in case the talks come to a close and no agreement is reached, but time being firmly on the side of the Islamic Republic and Velayate Faqih, Iran's reaction will surely mirror this reassuring fact.