Regarding the impactor...
I remember the Cuban Crisis. I may have mentioned before. that, as we were situate in eye of Venn Diagram between three juicy UK thermo-nuke targets, we did not expect to survive intact. We converted under-stairs nook into shelter. Brought in garden tools etc. Tied ladders / planks against side of stairs to protect access. Lifted floor-boards to access crawl space, gathered camping gear, blankets and winter clothing. Collected vittles and 'Collis Browne' mix. Former was 'camping' stuff, which even I understood. Latter, a Victorian opioid mix that would leave you giggly while your open fracture was splinted & stitched, your 3rd-degree burns debrided. Or 'ease out' several terminally ill elephants. And we had a very special bottle of spiked spirits guaranteed to take-down a posse of 'Bad People' if yielded under duress...
My young brother and I slept under stairs, as we feared a thermo-nuke in double-bottom of false-flagged ship in estuary, so no warning. Rest of family would come running if sirens sounded. We had our eclectic book-shelf, my school-books etc. Worst case, I was expected to break out via the crawl-space, raise my brother on 'Physical Geography', my beloved 'Outlines of Science' and, um, 'Kipling', per 'Deadlier than the Male' and 'Jungle Book Rules'. Helluva responsibility to give a shy adolescent, but...
Apophis...
Most of world might handle its approach rationally, but would take scant few to lose their cool and kick off. With sundry nuclear powers targeting in-bounds, plus last-ditch, in-atmosphere strikes, and the probability of debris and/or fall-out landing on noisome neighbours, it all could have gone very, very badly.
I reckon equivalent would have been 1918~19 with many nations exhausted, the Spanish Flu rampant and the Russian Civil War. Combined with the 'Partition of India', the 'Black Death', the Turkish pogrom in Armenia and a dozen other infamous mega-ghastlies...
I'm glad it missed.
FWIW, IIRC, ash distribution shows Toba blew in season when the Monsoon swept much of fall-out away from Africa and southern Asia. Had its paroxysm been six months earlier or later, they'd have caught a lot more grief. Fluorosis added to 'volcanic winter'...