Perhaps this will help clarify the historical record.
The Roman forces retreated from JERUSALEM in 66 CE but then returned to JUDEA the following year in April 67 CE, destroying towns and people, before finally tackling Jerusalem in 70 CE.
So Christians in JUDEA in 66 CE only had a few short months in which to get out of Judea. Those in Jerusalem would have risked their lives by delaying their escape in 66 CE..
https://en.wikipedia.org/wiki/First_Jewish–Roman_War