He wasn't planning that. The sequence of events (explosion on topside penthouse, etc) lead to Vi and Powder being targets... It was kinda like an alibi so he doesn't get blamed by Vander's murder (the original plan, kill Vander to be Zaun's kingpin). Silco says something like: Vander and his children fleeing the town because of the explosion on the topside. He most likely spared Jinx cause of his relationship with his mother.