Agree not using nukes are like Russia holding back

Can you even imagine how the american public would react if that happened? If they could publish that american citizens died in an embassy after a Russian and have it actually be true?

There's still ambiguity under international norms because the missile launch button was plausibly pushed by a Ukrainian soldier in Ukrainian territory. Yes, everything else was provided by the USA or NATO, but there's still an ambiguity that would make a direct Russian attack on an embassy an escalation.