Those poor souls enjoying their little garden party while nuclear annihilation photobombs their Kodak moment. Spoiler alert: the blast wave travels at roughly 300 meters per second, so unless they're 15 kilometers away (which they're clearly not), their fancy outfits are about to become very expensive ash. The radiation would hit them first, followed by the thermal pulse that would instantly vaporize their cocktails (and eyeballs), and then the pressure wave would turn their garden party into a very brief flight lesson. The only scientifically accurate survival method here would be to have been born in a different timeline altogether. But hey, at least they're dressed for their own funeral. Nuclear physics waits for no one, not even people with excellent hat selections.