When Isabelle and her mother's Schengen visa were finally processed, the three of them made the decision to fly to Venice on the same day, late at night.
They didn't want to prolong being in New York any longer, nor take any chances with the situation as long as Kritsana remained in New York. Anything can happen; he already proved to them that even the detention room in a police station can't hold him down.
With safety being their top priority, they kept their travel plans discreet, only sharing the information with their immediate family and Isabelle's closest friends. The goal was to arrive in Venice without drawing any unwanted attention or facing the possibility of being followed.