1)
Why does it say "b'Eineicha"?
1.
Radak: You will see them die. They will not dwell b'Seser Elyon like you! You will have Shalom.
2.
Malbim: You will investigate those falling around you, and see that Resha'im are eradicated; Hashem punishes them with Hashgachah.
2)
What is "Shilumas"?
1.
Rashi: It is eradication.