Yes, very true. :tu:
My 'plan' would only realistically work with the purchase of another ICN-BJS R/T ticket, adding another ~U$370 person.

I had to skip the last sectors twice with MU:

-once was on a purely domestic itinerary via SHA, it was cheaper then to end the trip at SHA and I even got a refund of airport taxes for the second sector;
-on a HKG-KMG-RGN return ticket, my plans changed at the last minute and upon arrival at KMG, I went on a domestic flight with MU the same day.

No problem.

Skipping last sectors is never a problem.
What the OP wants to do is skip a middle segment, and then fly the rest of the ticket.
That is a no-go - the balance will be cancelled if the middle segment is not flown.