Mount Vesuvius erupts in 79 AD, but the eruption effects are seen 240km away in Rome...?
Fortunately, the eruption has caused some beneficial consequences for the plot to develop, in a typical Hollywood manner. However, contemporary accounts, like those of Pliny the Younger, do not report significant effects of the eruption in Rome.
The series' scripts sometimes take liberties with historical reality. This is awkward for a historical series...
But the production is very well executed. The attention given to details is mostly worthy of an historical plot reminding of such eyes-popping scenes from Ben-Hur or Gladiator...
Apart from this episode, the series delivers its share of gladiators fights, Roman buildings reconstitution, power conflicts, etc. The spectator won't be boring.