Looks like Samaritan is now online.
Why exactly did Finch leave the others even though Reese didn't put a bullet in the senator's head? Then again, he propably knew that Decima would get the connections and he would be the first logical target, so I guess he wants to protect Reese and Shaw essentially from himself.
I saw it more as him rejecting the Machine (since it wanted them to kill -- possibly) rather than rejecting Shaw and Reese. The numbers being targets instead of victims or perpetrators seemed to greatly unsettle him. Maybe he's just dropping off the grid until he can reassess the new methodology of the Machine.