I would keep refreshing twitter. I would not be worried about my safety, but i would become worried about the people living in Ukraine and Russia.
I would first want to make sure the report was accurate. And hope that it wasn't. I have no faith in what the current president would do, his actions are as dangerous and erratic as any adult man with power I have ever witnessed.
My wife and I have a list of items we would want to acquire in large quantities should something like this happen. So I would notify her, she would go to Walmart with her list and I would go to Home Depot with my list. We'd both take checks in case the internet stopped working for credit cards.
If I found out that Russia detonated a baby nuke in Ukraine? I'd probably get myself a cold drink and watch a movie, play with my cats, hug my wife, go out to dinner... all sorts of crazy stuff. Then fall asleep.
We've been "prepping" for years. One trip to the store won't help much... food... water (PURIFICATION!)... ammo... medicine... tools... seeds... reference books.. hygiene supplies... barter items...
First, I would go make sure the candles and matches are still where I remember putting them. Second, I would look for some different sources with different political biases from different regions, see if its more rumor being reported as 'fact'. Third, I would go check that my gas cans are full, and if not (likely not...), I'd head into town to stock up an unethanolized. And if all the power doesnt go out in the next 12 hours and the Army base to the south is still pounding away at artillery drills instead of vaporizing in nuclear hell, then I'll just know where my candles are and have plenty of gas for the mower in the spring. I really should just finally buy a geiger counter tho. Thx for the reminder.
I believe in starting out by having a certain minimal number of things you always take care of and then adding to those as time goes on. Like refueling your vehicles before they get below half a tank. And keeping a couple of 40 lb. bags of dry dog food in stock. Note, I have no interest in keeping my emergency stock where my family and I can survive the fall of civilization and completely rebuild it. My goal is to get enough to survive for a year. I figure if things don't turn around in a year then all is lost probably anyway.