Scattered, I don't think you get how this setup works.
Two people are cops. One always gets accurate results (unless framer), the other always gets the opposite result of the correct one (unless framer).
Even after a cop dies, we don't know their sanity. But what we do know is that one cop must always be getting right results and one always get wrong results.
This is useful to know because it functions as a parity cop: if one cop gets town on someone and the other cop gets scum on someone else, we know they share an alignment (or framer) since exactly one result is wrong. If they get the same result, we know the players have different alignments (or framer) since exactly one result is wrong.
If we make it to N2 with both cops alive, there will be four players alive, one being scum. Scum will simply kill one cop and frame the final VT, making it so the final cop has 100% useless results, since both of the other two players alive will check as the same alignment. That cop will be cleared, but their check won't have value.
Does that make sense?