(Painkiller spoilers) Hmm, if theres only a group of people in other cities that can help Khalil/Painkiller So in the Painkiller episode, it showed that Khalil/Painkiller wont truly be at peace until he executes the "kill" order on the Pierces.  And that said order acts like a GPS wherein its only triggered when the target is nearby. 

I know its his solo arc, but pretty hilarious how since its set on Earth Prime, there are many people that can help him. 

Barry through the means of science, Jon Jonzz through the means of powers, Sara through the means of control (like with her bloodlust).