Мафия 65. S1-ut system: criminal scum strikes back!

The last number that remains will be Sesame's, which means that one of two remains: 14 or 18.

"Completely" - does this mean ignoring natural defenses, any defenses at all, or something else?

Basically, everything. The target can only survive thanks to the rescuer.

For this, does the Engineer need to go to the Coordinator after her "death"?

Yes.